Skitch, the popular screen capturing tool has been acquired by Evernote, another service that I love, and they are making the program FREE (was $19.99) in the Mac App Store.
Skitch is your image swiss army knife. It makes it easy to screen capture, crop, resize, sketch then share really fast. With the free built-in skitch.com image hosting, Skitch is the fastest and easiest way to share your work and your life.
Evernote has also released a Skitch app for Android in the Android Market for FREE. It allows you to quickly draw attention to anything in a picture; take a snapshot of something awesome, draw an arrow and add a caption, then post the image on Twitter or Facebook. When you’re at a conference, snap a picture of the people you meet, annotate it with their names and save it into Evernote. Quickly sketch out a map, diagram or unicorn!