Preps Rulings

All-Hands
The additional cards accessed do not include cards installed in HQ. (JD Wiker, Netrunner-L, 1/3/97)

 Arasaka Owns You
Playing Arasaka Owns You during a run does not end the run. (Sparky, Netrunner-L, 6/27/96) 
If you are flatlined by unpreventable damage, you cannot play Arasaka Owns You. (Sparky, Netrunner-L, 10/18/96) Any prevention effect is also a condition for play. (Sparky, Netrunner-L, 12/2/96)

 Custodial Position
The additional cards accessed do not include cards installed in R&D. (JD Wiker, Netrunner-L, 1/3/97)

 Demolition Run
If you also have Armageddon installed, you may not give a Doom counter AND trash the rezzed ice on the fort; you must do one or the other (see notes on Armageddon). (JD Wiker, Netrunner-L, 2/4/97)

 Disgruntled Ice Technician
Ice with no subroutines on it (e.g., Hunting Pack as the only ice on a fort) can be considered to have had all of its subroutines broken. (Sparky, Netrunner-L, 9/5/96) 
You cannot use Disgruntled Ice Technician to derez the ice after using Dropp to break the subroutines on that ice. (JD Wiker, Netrunner-L, 1/6/97)

Edited Shipping Manifests
If you want to prevent the tag given by Edited Shipping Manifests, you cannot pay for the tag prevention effect (e.g., Nasuko Cycle) using the bits from that Edited Shipping Manifests. Since the Runner must process a card's effects in order, he or she does not get the ten bits until after the tag is given. (Netrunner FAQ v.1.0, 5/22/96) 
If the run is successful and the Corp has no bits, the Runner accesses cards as normal. (Sparky, Netrunner-L, 8/6/96)

 Executive Wiretaps
The additional cards accessed do not include cards installed in HQ. (JD Wiker, Netrunner-L, 1/3/97)

 Forged Activation Orders
ERRATA: Forged Activation Orders has no effect on a piece of rezzed ice; the card should say "Choose an unrezzed piece of ice." (Official Netrunner Rulings, 4/21/97)

 Hunt Club BBS
All choices about which and how many cards will be exposed are made before any of them are exposed. (Netrunner FAQ v.1.0, 5/22/96)

 Kilroy Was Here
You may trash agendas even if an effect prevents you from scoring those agendas (e.g., Red Herrings). (Sparky, Netrunner-L, 6/25/96)

 Lucidrine (tm) Booster Drug
You may use the bits from Lucidrine Booster Drug to pay for trashing nodes and upgrades accessed during that run. (Wendy Wallace, Netrunner-L, 5/28/96) 
Preps and Operations go to the trash after they're fully declared (i.e., after all decisions are made) but before they're resolved; Lucidrine Booster Drug goes into the trash before any cards trashed as a result of the run and before the card you lose to the brain damage caused by Lucidrine Booster Drug. (Sparky, Netrunner-L, 8/27/96) 
You don't take the brain damage until after the run is complete, so if you score enough agenda to win (or meet another winning condition such as trashing Nevinyrral), you never suffer the damage. (Official Netrunner Rulings, 4/21/97)

 misc.for-sale
ERRATA: misc.for-sale will read "successfully trashed" instead of "trashed." You cannot get bits from misc.for-sale if you use Joan of Arc to prevent programs from being trashed. (Sparky, Netrunner-L, 7/24/96)

 On the Fast Track
If you trash cards that you don't see (cf. Death from Above), and you play On the Fast Track, you can ask the Corp if you trashed an Advertisement or Transactions card this turn, but you may not look at the cards or the Archives to verify this. If necessary, you can ask a third party to verify the Corp's answer. (Tom Wylie via JD Wiker, 3/11/97)

 Organ Donor
Preps and Operations go to the trash after they're fully declared (i.e., after all decisions are made) but before they're resolved; Organ Donor goes into the trash before any cards are trashed from your hand. (Sparky, Netrunner-L, 8/28/96)

 Pirate Broadcast
You only get one chance to run each fort; if something (e.g., Siren) misdirects you away from a fort, you can't run it again. (JD Wiker, Netrunner-L, 2/5/97)

 Prearranged Drop
The bits are gained as soon as the agenda is accessed, so the Runner can use these bits to pay trash costs or pay costs for stealing agenda (e.g. Red Herrings). (Skipper Pickle, Netrunner-L, 5/18/98)

 Promises, Promises
The Runner scores the additional agenda point as soon as the agenda is accessed, but the Runner cannot win the game until after all cards in the fort are accessed and their effects dealt with (See Sparky's Run Chart). (Skipper Pickle, Netrunner-L, 5/18/98)

 Remote Detonator
In the case of a misdirected run, the ice trashed is the ice on the fort that was accessed (e.g., the Runner runs on Archives but accesses cards in HQ; the ice on HQ is trashed). (JD Wiker, Netrunner-L, 3/5/97)

 Rush Hour
The additional cards accessed do not include cards installed in R&D. (JD Wiker, Netrunner-L, 1/3/97)

 Senatorial Field Trip
If the ice is not rezzed, Senatorial Field Trip has no effect. (Sparky, Netrunner-L, 9/5/96)

 Sneak Preview
If you use Sneak Preview to install a program, then later trash that program, it will not return to your hand. (Sparky, Netrunner-L, 7/17/96) If the program ends up on a Microtech Backup Drive, or leaves play for any other reason, it won't return to your hand. (Tom Wylie, 8/26/97)

 Social Engineering
The Corp has the right to count the Runner's bits before the effect starts, but not once the guessing game begins. (Sparky, Netrunner-L, 7/25/96) 
You must encounter a piece of ice before you pass it. If the Runner chooses an unrezzed piece of ice, the Corp has a chance to rez that ice. (Sparky, Netrunner-L, 7/26/96) 
Social Engineering only allows you to pass that piece of ice one time during that run. (Skipper Pickle, Netrunner-L, 11/4/97)

Subliminal Corruption
It's not legal to trash something that's already in the Archives, so you can't give the Corp bad publicity for advertisements that are already in the Archives. (Official Netrunner Rulings, 4/21/97)

 Synchronized Attack on HQ
Each card for which the Corp pays 2 bits is no longer available to be discarded. Essentially, effects that force the Corp's discards to be random (e.g., Cockroach) are worthless when combined with Synchronized Attack. (Tom Wylie via Sparky, Netrunner-L, 8/7/96) 
Unofficial ERRATA: Sparky says, "To make the function of [Synchronized Attack on HQ] more clear, we're CONSIDERING: 'For each card stored in HQ, Corp either pays[2] or discards that card.' This better explains why the card interacts the way it does with discard modifiers, like Cockroach counters." (Sparky, Netrunner-L, 8/9/96)

 Total Genetic Retrofit
If multiple Total Genetic Retrofits are played, their effects are cumulative (i.e., if you play two Retrofits, you avoid your next two tags) (REVERSEs a previous ruling). (Skipper Pickle, Netrunner-L, 9/30/98)

 Valu-Pak Software Bundle
You get 5 actions and 1 bit, not 5 actions and 1 bit per action. (Sparky, Netrunner-L, 6/18/96) 
You must use the actions you gain from Valu-Pak Software Bundle immediately or forfeit them. (JD Wiker, Netrunner-L, 12/16/96) 
The bit must be spent "during" one of the actions gained from Valu-Pak Software Bundle--you cannot use it on special effects that occur between those actions. (Skipper Pickle, Netrunner-L, 10/4/98)