If you don't want to pull out the inflated graphics editor for a simple crop job, then you'll want to give SnipShot a try.

SnipShot is streamlined - there are only five tools to choose from (undo, resize, crop, rotate, adjust), so your choices are limited. But SnipShot is not about complicated; this is a barebones graphics editor for when you just need to smallify that overwhelmingly huge pic of Tom Selleck for your fan blog. Snipshot also allows you to save your image in a variety of forms: .gif, .jpg, even to your Flickr account.