Screen capture tools are a dime a dozen. Indeed, Windows Vista even comes with Snipping Tool, an awesome utility in its own right. But Snagit has features you don't tend to see in most screen cap programs, like the ability to capture a long scrolling browser window or document that's taller than the screen. It also includes its own graphic editor and has the ability to take simple screencast video.
Of course, this isn't rainbow and unicorn day. The version that TechSmith is offering is Snagit 7.2.5 -- an older version that isn't compatible with Vista. If you can live with that, surf over to the promotional page to download Snagit and get a free software key. On the plus side, if you want to, you can immediately step up to the latest version at TechSmith's upgrade price -- $25.