(Updated June 18/2008) If you’re looking for a list of ping sites for use with WordPress, check this list, compiled from a number of sources on the Internet. Note the list is much smaller than previously, due to sites going offline, and closing ping servers due to splog (spam blog) sites.

This list is provided ‘As Is’ with no warranties nor guarantees:

http://rpc.pingomatic.com/
http://rpc.technorati.com/rpc/ping
http://1470.net/api/ping
http://bblog.com/ping.php
http://ping.feedburner.com/
http://ping.weblogalot.com/rpc.php
http://pingoat.com/goat/RPC2
http://rpc.blogrolling.com/pinger/
http://rpc.weblogs.com/RPC2
http://topicexchange.com/RPC2
http://www.bitacoles.net/ping.php
http://www.blogdigger.com/RPC2
http://www.popdex.com/addsite.php