Edit Feb 2010: New BugTracker.NET Screen Capture Utility!
Ok, the name isn't very politically correct, but the screen capture utility for BugTracker.NET and other trackers called "Bug Shooting", by Alexej Hirsch, works great with BugTracker.NET.
I don't know or not if it was Joel at FogBugz that first came up with the great idea of screen capture utility that integrates with your bug tracker, but that's where I got the idea for the BugTracker.NET screen capture utility. Some other trackers also either officially come with a screen capture utility or provide an API that allows third parties to develop one, for example, Gemini, Jira, Mantis. These screen capture utilities change the way people behave. If you are focused on testing some feature but in the course of that testing you happen to see something odd on the screen, not part of the area you are focusing on, then with these utilities you can quickly capture what you see on the screen and post it to your tracker in under 10 seconds. That's not much of a detour from your focus. There's a difference between how people behave when faced with a detour that takes 10 seconds versus one that takes, say, 40 seconds. You really will get more screenshots in the bug reports from your testers if you can get them set up with one of these utilities that works with your tracker.
Bug Shooting is a .NET 2.0 application. If for some reason you don't already have the .NET framework running on your machine and refuse to install it, then use my screen capture utility. My utility does not require installation of the .NET framework. But that's its ONLY advantage. In every other way, Bug Shooting is better. It has been stable on the two computers I've installed it on (Gemini's tracker, which I initially liked tended to crash frequently for me) and it has more features than any of the utilities from the me, FogBugz, and Gemini.
It currently works with BugTracker.NET, FogBugz, Gemini, and OnTime. Maybe Alexej has some more trackers on the way that he plans to support. It's not only a good tool for use with a bug tracker but it's a good tool for general purpose screen capture purposes. Tools for croping, annotating, saving it as a file, importing an existing file.
Highly, highly recommended.