If you are frequently uploading screenshots to post on your blog or discussion forums, ShareXmod will come in handy. Actually, one of my friends is a co-developer.
Other than being able to take screenshots of basic areas like the entire screen, an active window and cropped screen area, it’s capabilities extend to the following types of screenshots; even the components like toolbars inside applications! (I took the following screenshot from it actually)
The best thing about it is not the great screenshot taking capabilities, but sharing features. It supports multiple image hosting sites such as Imageshack, Photobucket, Picasa (and more) and further lets you shorten the URL so that you can paste them to your twitter status message, for example. Instead of letting you upload the photos anonymously or publicly – like most other tools would, it actually lets you log into your own account of the image hosting site of your choice. You can also upload existing files.
Download
You can download ShareXmod from here: http://code.google.com/p/sharexmod/downloads/list