Skitch

Skitch - Evernote

Skitch allows you to annotate pictures, maps, and web browsers. It is part of the Evernote family of apps. 

 

You can choose a photo from your camera roll, take a snapshot from maps, search using a browser then take a snap and start annotating.

As well as being able to freehand draw, type text you can also pixelate faces or sensitive information. 

It's a very useful tool whether you want to use it for brainstorming, pointing out something on a photo or correcting work!