Spamhaus tracks the Internet’s Spammers, Spam Gangs and Spam Services, provides dependable realtime anti-spam protection for Internet networks, and works with Law Enforcement to identify and pursue spammers worldwide.
Wanadoo.es – too many compromised Windows boxes to count! http://www.spamhaus.org/sbl/sbl.lasso?query=SBL15575

The SBL is an international anti-spam system maintained by The Spamhaus Project and used by Internet networks to protect customers from spam sources and spam services. The SBL lists only IP addresses (not domains or addresses). If you are unable to send email due to SBL listing, please contact your Internet Service Provider and show them this page, but only if you are an ISP