ICUP (Image Capture and Upload Program) is a small free tool which makes it easier to take and share screengrabs.
Using the program can be as simple as pressing the hotkey (F9 by default), clicking and dragging to define the rectangle you'd like to capture, and pressing Enter. Your image will then be saved and uploaded to the image sharing site imm.io, with the link copied to your clipboard, ready for immediate sharing.
If you need to take several captures then you'll appreciate ICUP's history list. You're able to view a list of image URLs; clicking on any of these displays a preview of that grab, and right-clicking the link displays options to edit the image in Pixlr, re-copy its URL to the clipboard, or remove it from the list.
There are a few configuration options, too, although they're not so easy to spot (you need to click the arrow to the right of the "Thumbnail Page" button). Here you're able to define a new hotkey, and tell the program to display the image after its been uploaded, along with one or two smaller tweaks.
The main weakness here is that you only get one capture type: a freehand rectangle. If you want to capture the whole screen, or a window, then you have to move your mouse to one corner (with pixel-perfect positioning), click the left mouse button and drag to the other. It's not difficult, but it's harder than the regular Windows PrtSc and Alt+PrtSc options, an issue in a program which is trying to save you time.
Still, ICUP is very new, and we suspect more capture types will be added, along with other goodies, in the near future. But in the meantime, if you're just looking for quick freehand captures then ICUP works well, and is easy enough to use.