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)
The wording on Darkness Energy from the EX Ruby & Sapphire expansion says: "If the Pokémon Darkness Energy is attached to attacks, the attack does 10 more damage to the Active Pokémon". Does this mean that you get to add +10 even if an attack does no damage at all to the Defending Pokémon (i.e. EX Sandstorm Murkrow's "Surprise" attack)?
No, it still applies only if there was initial damage to add to. So in other words, you still have to do some damage in order to have "10 more" done.
Source: PUI Rules Team (2003-09-18)
I've noticed that some cards say "Does 10 damage to the Defending Pokémon", whereas others say "Put 1 damage counter on the defending Pokémon". Is there any reason for the different wording? I've spoken to someone who says that you do not apply weakness or resistance for attacks where it specifies Damage Counters; is this the case?
There is a difference. As you mention, weakness and resistance are not applied when placing counters. Also, things like Defender and Metal Energy will not block Placing Damage Counters. It will not trigger things like Base Set Machamp's Strike Back. In the steps of resolving an Attack, "placing Damage Counters" counts as an Effect of the attack, it is not part of "doing damage".
Source: PUI Rules Team (2003-09-18)
Can you have 4 Electabuzz and 4 Electabuzz-EX in the same deck?
Yes, you can play 4 Electabuzz and 4 Electabuzz EX in the same deck, as they are considered different cards (similar to the ruling for Trainer Pokémon).
Source: PUI Rules Team (2003-09-11)
In the EX:Sandstorm set, there are 2 identical versions of Marill, but one has a retreat cost and one does not. Which one is the correct version and how shall the 2 different versions be played?
This appears to be a fairly common mistake in the set. Play the card as written; if you have the Marill with the free retreat you may play it as such.
Source: PUI Rules Team (2003-09-11)
We cannot attack our partner in Team Battle - I had somebody try that at Worlds while I was judging team. They didn't want to flip to use an Eeeeeeek attack so they aimed at their patner.
Correct, you cannot attack your teammate.
Source: WotC Chat (2003-06-12)
A Judging question -- a Pokemon that has 5 or 6 cards attached to it is on the table. A player throws a six sided dice and it lands half on the table and half sitting on this big stack of cards at about a 25 or 30 degree tilt. Is this similar to the "flat coin ruling where the coin flip counts even if it lands in the damage counter or half on cards. What do we do? An experienced player gently pushed the cards out from under the dice to see if they stayed put. Two new players started debating just where the dice actually landed -- under a lot of cards or just a few???
Anything less then a 45 degree angle is fine.
Source: WotC Chat (2003-02-20)
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)
When both Active Pokemon are Asleep, who tries to wake up first?
Umm, we have no idea why it would matter. Usually you do them at the same time. If for some future reason it would matter, then the player whose turn is next would flip first.
Source: WotC Chat (2002-11-21)
In TMP, if I play a Supporter on my opponent...since it's played on him I cannot use any more supporters my turn...but he can use them on his turn correct?
Correct. [Ed. Note: Just for clarification, the supporter action itself must be played during the current turn; it cannot be held over until the opponent's turn. The answer here indicates that the other player may play a Supporter on their turn if they wish.]
Source: WotC Chat (2002-09-19)