i have 2 512 chips in there. So if he does have 2 256 chips, i can hook him up with these i guess
Yes you can! Your friend's memory will be 512mb+256mb = 768mb. It doesn't hurt to give it a try, the worst that can happen is your MB will beep if the RAM is not compatible. Simply put the old RAM(s) back and your problem will be solved.
Should be ok, all MacBooks use 200 pin PC2-5300 so upgrading the (2) 256 with the (2) 512 will work, just make sure you buy a pair of 2 gig chips, BTW will your MacBook recognize the 4 GB, it has to be an Intel Core 2 Duo not the older Core Duo.
I just upgraded to 4 gigs on my MacBook, it ROCKS!
You will be glad you upgraded.