The wording of Great Ball is now as follows, "Look at the top 7 cards of your deck. You may reveal a Pokémon you find there and put it into your hand. Shuffle the other cards back into your deck." This card works very differently now; it can no longer search the entire deck for a Pokémon and put it directly onto Bench.
Source: TPCi Announcement (2011-04-11), PUI Rules Team (2011-05-05)
Can I play Rare Candy on a Basic Pokémon to evolve it into a Stage 1 even though that Pokémon could evolve that turn normally?
No, this is no longer permissible [per BW rules changes].
Source: PUI Rules Team (2006-01-05), TPCi Announcement (2011-04-11), TPCi Announcement (2011-05-05)
Can I use Rare Candy on [my] first turn of a game (when Pokémon are not normally allowed to evolve)?
No, this is no longer permissible [per BW rules changes].
Source: PUI Rules Team (2004-07-22), TPCi Announcement (2011-04-11), TPCi Announcement (2011-05-05)
The wording of Defender is now as follows, "Attach Defender to 1 of your Pokémon. Discard this card at the end of your opponent's next turn. Any damage done to the Pokémon Defender is attached to by attacks is reduced by 20 (after applying Weakness and Resistance)." Defender now protects against all attacks, even ones not made by the opponent.
Source: TPCi Announcement (2011-04-11), PUI Rules Team (2011-05-05)
Can I use Rare Candy on a Pokémon's first turn in play? For example, can I place down a Wurmple and then use Rare Candy on the same turn to evolve it into Dustox or Beautifly?
No, this is no longer permissible [per BW rules changes].
Source: PUI Rules Team (2003-09-11), PUI Rules Team (2004-07-22), PUI Rules Team (2011-04-11), PUI Rules Team (2011-05-05)
The wording of PlusPower is now as follows, "During this turn, your Pokémon's attacks do 10 more damage to the Active Pokémon (before applying Weakness and Resistance)." This card no longer attaches to a Pokémon when used.
Source: TPCi Announcement (2011-04-11), PUI Rules Team (2011-05-05)
Can I play Professor Juniper if it is the only card in my hand, and then draw 7 cards?
Yes, you basically discard your remaining hand of zero cards, then you draw 7 cards from your deck.
Source: Black & White FAQ (2011-04-28), PUI Rules Team (2011-04-28)
Can I use VS Seeker to retrieve a Supporter that was played during this turn or do I have to wait until my next turn?
You can use VS Seeker whenever a Supporter card is in the Discard Pile, even if it was played during this turn.
Source: PUI Rules Team (2011-04-28)
Can I place all 4 cards that I looked at with the Trainer card "Research Record" at the bottom of my deck? Or can I place all 4 cards on top of my deck?
Yes, you can put as many of the four cards on the top or on the bottom any way you like (except face-up).
Source: Call of Legends FAQ (2011-02-10), PUI Rules Team (2011-02-10)
Do the individual pieces of LEGEND Pokemon count toward the 6 Pokemon needed for a player to declare themselves a winner when "Lost World" is in play?
Yes, each LEGEND Pokemon card counts as one Pokemon toward the requirement.
Source: Call of Legends FAQ (2011-02-10), PUI Rules Team (2011-02-10)