Anyone know of a good techie website

[Vanhalen]

Ive just bought a PC off my mate for £110 to replace my IBM Thinkpad 600X, the laptop was great but its a bit out of date now, the new PC is a 1.9celeron with 512mb ram, but I really want to ramp it up with a new motherboard, a dual core P4 graphics card, basically pretty much everything, I was looking if anyone knew of a website that could tell me what parts are part of which era, for instance when DDR2 ram replaced DDR ram and so forth, so I know I'm buying the right stuff, I know what I want/need, just not sure of the exact types to buy(and yes before anyone says anything, I know I need a new motherboard for the P4)

[Dimensions]

Try newegg.com