Project Honey Pot http://www.projecthoneypot.org/" onclick="window.open(this.href);return false; maintains a database of email spammer and dictionary attack IP addresses.
StopForumSpam http://www.stopforumspam.com/" onclick="window.open(this.href);return false; is a site for searching an IP address having spamming history. Some IP addresses are purposefully created for spamming, while others can be hijacked IP addresses.
To those running a forum, these may be helpful, as they also provide the country of origin, which is a great help when a new member declares their residence in one part of the world, but their IP is located in another nation.
