Semi off topic: COD rentals

[Jafo]

Hello,

If this isn't the forum for this question, please forgive me for asking
here.

There seems like a lot of people on this list that run "server rental"
operations. Just curious how people are doing that cost effectively?
Obviously one can't run each customer's game server on seperate hardware.
Are people using some sort of "virtual linux" installs to run multiple
servers on one box with seperate IP addresses? If that is the case how
many servers would one dual 2.4 Xeon w/2gig RAM run?

Thanks,
Jafo