well ideally you want ram that will match your own in speeds. its a bit hard to tell cus from the spec on the site, but there should be something in the literature about it. im pretty sure it will be ddr2 it just the speed that you need to check.

then i remembered the one good thing that the tech guys are good for

http://support.thetechguys.com/layout.aspx?ID={c6641bdb-d818-4baf-b08e-6ed04b832a02}&CatID={f83a6008-eb96-4455-a2eb-dbc0c148e43a}

so its ddr2 running at 5300

but your motherboard can support upto 6400.

you have four ram slots so its up to you.

i would advise for the most cost effective way to upgrade get a 1gb 5200 chip, leaving you with space to ad another later.

i checked ebuyer for you and they have

Corsair 1GB Kit (2x512MB) DDR2 667MHz/PC2-5400 Memory Non-ECC Unbuffered CL5 Lifetime Warranty - Ebuyer

but these would take up all your slots so

Corsair 1GB DDR2 675MHz/PC2-5400 XMS2 Memory Non-ECC Unbuffered CL4(4-4-4-12) Heat Spreader Lifetime Warranty - Ebuyer

is a better buy and you could get 2 and triple your ram.

ive put all the other ram that is avaliable that would work. so price is just the major factor. kingston, crucial and corsair are all wikid ram makes and reliable.
Crucial 1GB DIMM 240-pin DDR2 667 MHz PC2-5300 CL3 1.9V unbuffered non-ECC - Ebuyer
Kingston 1GB 667MHz/PC2-5400 DDR2 ECC Fully Buffered CL5 Dual Rank x8 - Ebuyer
Kingston 1GB DDR2 667MHz/PC2-5400 Memory Ecc Fully Buffered CL5 Intel Standard 1.8V - Ebuyer

so really its just a matter of price and taste. they should all work and drastically improve your pc.

hope this helps.

peace