The new modified rules state you may only retreat once per turn. If you use a trainer to Switch your Pokémon, can you still retreat that Pokémon? Or does the Switch count as your one retreat per turn?
Switch does not count as your one retreat per turn. If it did affect it, I would imagine it being written as "(This counts as retreating your Pokémon)".
Source: PUI Rules Team (2004-06-03)
If you use an Energy Search and don't find any Basic Energy, can you then play another Energy Search even though you know it will fail?
Yes, you can search for energy cards even if you know you won't find them. They exist as legal cards, therefore they can be searched for.
Source: PUI Rules Team (2004-01-15), PUI Rules Team (2004-01-22)
If you use an Energy Search and don't find any Basic Energy, do you still discard the Energy Search?
Yes, you would still discard it.
Source: PUI Rules Team (2004-01-15)
Could you Rare Candy a Pokémon and NOT play an evolution on it just to get rid of the Rare Candy?
No, you cannot discard a card for free. You must be able to attach the Stage 2 card, or you cannot use the Rare Candy.
Source: PUI Rules Team (2003-10-30), PUI Rules Team (2003-12-04)
Could I use the effect of a Stadium card already in play, then play a Stadium card from my hand to remove the old stadium, and still be able to use my new stadium's effect?
Yes, provided you have not already played a Stadium card that turn [and the new one has a different name].
Source: PUI Rules Team (2003-11-06)
Can I use Rare Candy on a Pokémon that has already evolved normally that turn?
No you cannot, because Rare Candy can only evolve Basic Pokémon If you evolved a Pokémon already this turn, it would not be a Basic any more.
Source: PUI Rules Team (2003-10-23)
Can you use Rare Candy to evolve a Mysterious Fossil into an Omastar or Kabutops, or use it on a Root/Claw Fossil to evolve into Cradily/Armaldo?
It can. It counts as a basic Pokémon while in play. Omastar, Kabutops, Cradily, and Armaldo are Stage 2 Pokémon; you could use Rare Candy on the Fossil trainer to skip to them.
Source: PUI Rules Team (2003-10-16)
What does "This counts as evolving that Pokémon" mean, in game terms?
It counts towards the one evolution per turn for that Pokémon (with exceptions for Trainers and Pokémon Powers that break that rule) and removes Special Conditions on that Pokémon.
Source: PUI Rules Team (2003-09-26)
Can you play 2 TM's together on your active Pokemon?
Yup. One attack per turn, doesn't matter if you have two copies of it. You can only use one cube to attack. You don't have two attacks.
Source: WotC Chat (2003-02-13)
Can Pokemon be Knocked Out partway through completing the Trainer card?
A Pokemon cannot be Knocked Out partway through the Trainer card. You must complete all of the actions of a Trainer card BEFORE you check for game state checks (to see if a Pokemon is Knocked out for example).
Source: WotC Chat (2002-03-06), WotC Chat (2002-03-07)