Well, as my subject states - I am looking to set up my own home lab to do some pentesting/general exploration. My problem exists with hardware, and the only solution I can come up with would be a virtual network amongst my two boxes. Then arises the question, can my boxes handle numerous virtual machines? The two set ups are as follows:

Celeron 2.5Ghz
512MB Ram
Onboard Video (Generic Intel)
120GB Hard Drive
Running LAMP (Mandrake ATM) - Switching it to BT2.

P4 2.8Ghz
768MB Ram
Onboard Video
80GB Hard Drive
Currently running XP (I had it set up with an Original XP disc from like 2001, no updates done on it and watched it get probed and attacked and sniffed all the packets..it was great fun) but I will probably turn this into an Ubuntu LAMP server.

AMD64 3500+
1GB Ram
100GB Hard
These are just two old systems I've come into and can use for my aforementioned test lab. I plan on using VMware Server and perhaps running another 2 linux distros on SYS1, and leaving SYS2 as just the server. Then, I can attack away and such on my network.

So ultimately my question being, if you had such a set up (hardware to work with), how would you set up your lab?

Any suggestions would be much appriciated - oh and by the way, I am new here and I've browswed around quite a bit and seem to be enjoying the community so far.