U can get a 256MB stick and ad it to your existing RAM = 512MB.
Crucial, Kingston are really decent, and not usually much more than
some of the lesser known, less trusted brands.
Yes, very very easy. Have the machine off, ground yourself (hold onto bare metal on the case while its plugged in) unplug, and install. thats it.
yay i got 256 mbz and installed now im at 512 and i can tell a huge difference, battlefield 1942 loads levels 1:21 seconds faster than it did before! a whole minute and 21 seconds! it was a good investment....