Also a quick tip for those using Windows 7, there is a neat little program called Snipping Tool. Click Start->All Programs->Accessories->Snipping Tool. (Alternatively you can press Start then type Snipping Tool.)

Simply Click n Drag the area you wish to post online, it will then open a window that has your image. Click the save icon (or File->Save As), name it what you want, then upload it using Joe's above post.

This program is great for capturing only part of a screen, you do not have to use MS Paint or Photoshop to try and remove parts you don't want to post online (like your VIN number at the bottom of the Scan Tool window).