I bought 4GB of memory to upgrade my MacBook Pro (08) can the old memory be used to upgrade the memory in my wife's white MacBook.
Power Mac G5 iPhone 16GB, Mac OS X (10.5.1), 4 GB of Ram
Which '08? Early 2008 or Late 2008 (aka uni)? The Early 2008 model uses 667 MHz PC2-5300 DDR2 RAM, the same as the MB - so, those sticks can be used to upgrade your wife's machine. The uni MBP uses 1066 MHz PC3-8500 DDR3 RAM, and that cannot be used in the white MB (but is correct for the new uni MBs).