What is ROKSO, SBL, XBL, PBL or DBL?

ROKSO (Register of Known Spam Operations)

The Register of Known Spam Operations (ROKSO) database collates information and evidence on known persistent spam operations that have been terminated by a minimum of 3 Internet Service Providers for spam offenses.

SBL (Spamhaus Block List)

The Spamhaus Block List is a database of IP addresses from which Spamhaus does not recommend the acceptance of electronic mail.

The SBL is queriable in realtime by mail systems thoughout the Internet, allowing mail server administrators to identify, tag or block incoming connections from IP addresses which Spamhaus deems to be involved in the sending, hosting or origination of Unsolicited Bulk Email (aka "Spam").

XBL (Exploits Block List)

The Spamhaus Exploits Block List is a realtime database of IP addresses of hijacked PCs infected by illegal 3rd party exploits, including open proxies (HTTP, socks, AnalogX, wingate, etc), worms/viruses with built-in spam engines, and other types of trojan-horse exploits.

PBL (Policy Block List)

The Spamhaus PBL is a DNSBL database of end-user IP address ranges which should not be delivering unauthenticated SMTP email to any Internet mail server except those provided for specifically by an ISP for that customer's use. The PBL helps networks enforce their Acceptable Use Policy for dynamic and non-MTA customer IP ranges.

DBL (Domain Block List)

The Spamhaus DBL is a realtime database of domains (typically web site domains) found in spam messages. Mail server software capable of scanning email message body contents for URIs can use the DBL to identify, classify or reject spam containing DBL-listed domains

List of website to check if your IP is in the blacklist or to remove your IP from the blacklist:
http://www.mxtoolbox.com/blacklists.aspx
http://www.spamhaus.org/lookup/
http://cbl.abuseat.org/lookup.cgi
http://rbls.org/