For Delphi developers, a company called Peganza created two useful sourcecode analysers: Pascal Analyzer and Pascal Browser. I don't use them that often but when a project is close to it's deadline, they are useful to find some of the last minor issues.
There are probably a lot more code analyzers for Pascal. And for C++, C#, Java, VB.NET, Ruby, SQL, XSLT, Django, Forth, Perl, PHP and any other language that mankind has discovered, developed or created. Thus, it would be nice to have a long list of those here at SO, as a Wiki. Then visitors just have to check one location. :-)
Two kinds of tools will qualify for this list:
1) Tools which analyse code and report statistics and/or possible design errors.
2) Tools which turn code into readable or browse-able reports with indices and overviews.