For PS3 backward combatibility for PS2, do you need a PS2 controller and memory card? If so what kind works?

Answer 1

It is true that you need a memeory card adapter to use your old saves for PS2 games but if you plan on playing the game from the begining and dont care about old save you do not need any kind of adapter or additional memory card, You simply create a VIRTUAL MEMORY CARD on your hard drive to save PS2 and PS1 games. It is very easy to do and works fine. And PS3 controller works fine for PS2 games.

Answer 2

You need a memory card adapter.

http://www.circuitcity.com/ssm/Sony-Memory-Card-Adaptor-for-PlayStation-3/sem/rpsm/oid/166288/catOid/-16481/rpem/ccd/productDetail.do

No other controller is required besides the PS3 controller. The Ps3 is automatically compatible if you wanted to know about that. But if you want your old saves you'll need to buy from the above link or anywhere that sells them.