That is only true if you buy it directly from Apple.
The laptop memory is the same as PC laptops use, the Desktop memory is the same as PC desktops use. Go to any big computer store and you can get exactly what you need for the same price as a PC upgrade.
Order it online & it is even cheaper.
"The laptop memory is the same as PC laptops use, the Desktop memory is the same as PC desktops use"
No kidding? Apple.com memory is 2x store memory. 512MB is $150.
If you can get it, I recommend the $50 upgrade to a 5400 RPM hard drive. After more RAM, this is the best thing you can do for your computer.
I'm the proud owner of an original 1 GHz 17" Powerbook. The 17" screen is phenomenal -- being able to have two Word documents side-by-side on the screen is a major productivity enhancer.