I use a Mac at work and was recently introduced to Skitch in a training class. This application is really handy if you need to share images or screen shots with others. Skitch allows you to easily take a screen shot of what you’re doing and then annotate it to state what is important in the image. You can also easily do simple drawings and then share them. Once you have an image that you like you can just drag it to your email program, or if you sign up for an account with Skitch you can have the image uploaded there and accessible from their website.