I think that, if you're somewhat lucky, traceroute or tracepath may tell you. If you're on Windows, I think the tool is trcroute.exe, I can't remember.

$ /usr/sbin/tracepath www.perlmonks.org
 1:  192.168.2.53 (192.168.2.53)                            0.181ms pm
+tu 1500
 1:  router (192.168.2.1)                                   1.798ms
 2:  68.150.234.1 (68.150.234.1)                          asymm 47  92
+.337ms
[ deleted since it's boring stuff... -Tanktalus ]
 6:  ge-6-1.car4.Seattle1.Level3.net (63.211.200.29)       49.929ms
 7:  ae-1-54.mp2.Seattle1.Level3.net (4.68.105.97)        asymm  8  45
+.774ms
 8:  as-2-0.bbr2.Washington1.Level3.net (209.247.10.130)  asymm 11 187
+.939ms
 9:  ge-9-0.ipcolo2.Washington1.Level3.net (4.68.121.44)  asymm 11 194
+.012ms
10:  unknown.Level3.net (64.156.240.30)                   asymm 16 119
+.202ms
11:  192.168.1.191 (192.168.1.191)                        asymm 15 127
+.592ms
12:  perlmonks.pair.com (209.197.123.153)                 asymm 16 330
+.396ms reached
[download]

By looking at some of the last IP addresses reached, you may be able to determine the hosting site. Again, if you're lucky ;-) Usually the router at an ISP is owned by that ISP, so if the site is behind the router, you may be able to see its name and figure it out. In PM's case, the router at 192.168.1.191 doesn't seem to be named, so it's hard to tell, but pair.com does give PM an alternate name that makes it quite obvious ;-)