Xenu's Link Sleuth - Xenus Link Sleuth checks Web sites for broken links.
Octopus.do - Build your website structure in real-time and rapidly share it to collaborate with your team or clients. Start prototyping websites or apps instantly.
LinkChecker - LinkChecker is a free, GPL licensed website validator.
VisualSitemaps - Autogenerate visual sitemaps in seconds.
Scrutiny - Scrutiny for Mac helps you manage and improve any number of websites. Link check, search, full website spell check, XML sitemap generator, SEO audit
PowerMapper - Create visual HTML site maps and XML sitemaps for search engines of any web site quickly and easily.