[ale] OT: Calculating PC power consumption

[jb at sourceillustrated.com (John Wells)]

Gentlemen,

On my home DSL, I have roughly four boxes running at any give time: a
firewall/router, a DNS server, a web server, and a wireless VPN router.

I'd like to get a rough idea of how much these servers (particularly the
web server and dns server) cost me in $$ from power consumption on a
monthly basis.  I can't imagine it's overwhelming, but it'd still be nice
to know.

Anyone tried doing this before?

Thanks,
John