www.samspade.org
http://www.arin.net/whois/
Also, what you should do is compare this address you have which your friends using traceroute when your sure he's online.
See how this one I did on me shows the hops getting closer to Danbury CT (me)?
I omitted some hops and cut it off at Stamford Ct, for privacy purposes.
router-in.fifi.org 0% 1 1 0.98 0.98 0.98
dsl092-000-001.sfo1.dsl.speakeasy.net 0% 1 1 30.01 30.01 30.01
220.ge-0-1-0.cr2.sfo1.speakeasy.net 0% 1 1 21.93 21.93 21.93
ge-4-0-440.ipcolo1.SanJose1.Level3.net 0% 1 1 21.93 21.93 21.93
ae-1-55.bbr1.SanJose1.Level3.net 0% 1 1 21.99 21.99 21.99
so-0-2-0.mp2.Stamford1.Level3.net 0% 1 1 99.90 99.90 99.90
Edit:
You could also use the tools on this page:
http://centralops.net/co/