RegRipper

Author: 
Harlan Carvey

The RegRipper is an open-source application for extracting, correlating, and displaying specific information from Registry hive files from the Windows NT (2000, XP, 2003, Vista) family of operating systems.

Harlan Carvey has written a number of extremely useful tools, and his blog is an extremely useful resource. e.g.
http://windowsir.blogspot.com/2008/04/updated-regripper.html

It is also worth noting that regripper has its own dedicated forum. Additionally regripper can be harnessed together with Moyix's tool to parse registry information from Volatility.