Skitch has an easy to use fast application for your Mac. You can also upload and use Skitch.com if you are not a Mac user.

Skitch is great because you can take a screen shot of anything, mark tit up with notes and share with fellow workers, clients or friends.

Some of the cool editing features are:
– Cropping images by dragging the inner frame.
– You can enhance your images with arrows, text, shapes and even sketch.
– Images can be organized with tags and sets online.

Sharing features include:
– Share your work fast & easy on Facebook, Twitter, blogs, etc..
– Free image uploading and sharing whether you have a make or use their online version.
– Online users get a blog-like profile page for showing off their screenshots and creations.
– Easily upload to Flicker, MobileMe and even your own server
– Drag & Drop allows you to drag right into an email or to desktop

I definitely would recommend giving Skitch a try. I found it the best way for me to communicate with my programmers and clients by quickly marking up a screen shot with instructions.

See an Example Below: