If you are looking for a screen capture utility for Windows that’s super easy to use and doesn’t require installation (so you can easily carry it around on a USB Flash drive), check out Screensnapr.
You press the hotkey (the default is Ctrl+1), drag the mouse to select some rectangular area of your desktop screen and voila!
The URL of the captured screenshot image will get copied on to your clipboard that you can drop in an email message or post it anywhere on the web. (See related apps for publishing screenshot images on Twitter)
ScreenSnapr can also upload captures to your own FTP server. And if you work with multiple monitors, you can configure the utility to capture an image of both screens at once or each one separately.
ScreenSnapr.com - The utility is compatible with Windows 7 as well and it weighs just a little more than 100kb.