Checkbot

A tool to verify links on a set of HTML pages, a single document, or a set of documents on one or more servers.
http://degraaff.org/checkbot/

  CheckWeb

A program that analyzes the links included in HTML pages (internals and externals) and generates a report on those links.
http://www.algonet.se/~hubbabub/how-to/checkweben.html

  InSite

A free site management tool written in Perl.
http://insite.sourceforge.net/

  Ixsite Web Analyzer

Web site analysis tool that locates broken links, missing images, stale content and other problems.
http://www.ixacta.com/products/ixsite/

  Link Alarm

Web-based service for eliminating broken links.
http://linkalarm.com/

  Linkcheck Robot

A web spider that automatically checks the validity of links from a specified page and reports problems via email.
http://www.netmechanic.com/cobrands/workz/link_check.htm

  Linklint

A Perl shareware program that checks all local and remote links on a web site.
http://www.linklint.org/

  LinkScan

Link-checking and web site management tool.
http://www.elsop.com/linkscan/

  LinxCop

Multifeature link-checking tool.
http://www.filehouse.com/linxcop/

  NodeWorks

Provider of link monitoring and checking services.
http://www.nodeworks.com/

  W3C Web Walker

Application that can be used to check links, find bad HTML, map out a web site and download images.
http://www.w3.org/Robot/

  Xenu's Link Sleuth

A spidering software that checks web sites for broken links, images, frames, plugins, backgrounds, scripts and Java applets.
http://www.snafu.de/~tilman/xenulink.html