binfone.com (get an account now!)
I would not use anything under a P4 in production, and would recommend a nice Core2 Duo (or a Xeon if you can afford it!).
The cost of the software is free. I HIGHLY recommend purchasing the manager's manual.
If you are not sure about the software, you can TRY IT RUNNING ON A CD! (no installation, just burn the .iso and run it on the CD on any computer, after you reboot it will be like it was never there!)
www.vicibox.com (and there's a full .iso to install from on the same site for after you finish with the "Demo")
If you have problems, there is support available at EFLO.com (the owners/creators of the software) or here on this forum (from guys like me who use the software but aren't really associated with it). I install it also, and maintain it, and integrate it with other software (as do many of the users on this forum).