don't know what your budget is..
but i personally like Crucial memory.
they offer a 100% compatibility w/ your machine, so pretty much any machine.
i use the value RAM from them, and the same w/ every other pc i upgrade for friends/family...works everytime!
there are a lot of systems out there that may not be compatible w/ certain RAM , but Crucial is right on!
they are also known as Micron Tech...
1GB sticks are quite expensive now, i'd say if you're on a budget get a stick of 512mb...for now.