In several discussions at the RN Summit, the site-wide RN Link Checker seemed to be a hot topic - a lot of us are looking forward to it coming out.  I had promised several folks that I would share the URL to the freeware (Xenu Link Sleuth) that I use to check links.  It's a very basic program, and may give you more information than you need, but it's a good resource until RightNow has a site-wide link checker for us.

http://home.snafu.de/tilman/xenulink.html

Currently, I'm using it to correct links that are still going to our old knowledge base that need to be corrected.  The links are "good," they're just wrong.  

There are other programs out there - please feel free to reply if you're using something else.

-Carlota