PS3 utilizes Blu-Ray

[Solid Lifters]

What about the memory card? how does the memory card look like in PS3?

There is no need for one. With Blu-ray, you can save your game data straight to disc. But, there will be a memory card stick made for saving game data, if you need to. It will be a 256 to 512k memory stick that Sony already make. But, this is not yet confirmed.