This Yahoo! and MSN Backlink Tool returns:

• unique linking domains
• their IP addresses & unique c block addresses of the links
• links from .gov, .mil, .edu, or .ac.uk domains.
• This tool also bolds and autochecks domains that link from 5 or more pages. You can then requery the Yahoo! database and spider deeper than the 1,000 link limit.
• This tool uses the Yahoo! API, provides CSV outputs.
• This tool also links to the Internet Archives, WhoIs Source, and Google cache near each link.
• 403 errors means the tool is used up for the day.
• BE PATIENT WHILE RESULTS COME BACK!