Dave recently turned me on to GhostDoc , a (free) add-in for Visual Studio that automatically generates documentation. ( One of MSDN's 10 must-have add-ins in the last issue ). The VS2003 add-in has been available for awhile and a VS2005 version has also been released.
GhostDoc is a free add-in for Visual Studio that automatically generates XML
documentation comments. Either by using existing documentation inherited
from base classes or implemented interfaces, or by deducing comments from
name and type of e.g. methods, properties or parameters.
It's really a great time-saver for generating baseline documentation. It's pretty powerful if you follow a consistent set of conventions (you can customize the rules to fit your particular style).
Definitely worth a download.