Oops! You said MBP! Sorry! But the info still applies, I believe.
2 x 512 MB Hynix brand RAM was in my 2.2 Ghz Blackbook SR. I upgraded to Kingston KTA-MB667K2/4GR from newegg, which keeps getting cheaper after I bought it, grrrrrr.
But really any brand of RAM will suffice and should do okay.
Please note that there is currently a problem with SR MacBooks with 4GB of any RAM and running the Apple DVD Player. It will cause a hard crash/kernel panic. This is a known problem, just google it, or search here in MR forums. Perhaps consider going with 2GB or 3GB of RAM until this is resolved.
Good Luck!
http://www.newegg.com/Product/Product.aspx?Item=N82E16820134560