A list of rootkit detection and/or removal tools from publicly trusted sources:
Name, Vendor, Latest release
RootkitRevealer, Sysinternals, November 1 2006
Rootkit Unhooker, ep_x0ff (now working at Microsoft according to Rootkit.com), December 2007
F-Secure Blacklight, F-Secure, Unknown
GMER, GMER, March 2009
Microsoft Malicious Software Removal Tool, Microsoft, April 2009
IceSword, Unknown, September 2005
Please add any trusted tools that you know of to the list.