ResizeImage is a web tool that lets you quickly resize and crop photos online. The application is easy to use and no registration is needed. 

Simply...

• upload image from your computer and
• chose one of two resizing options: 
  • Basic resize - Lets you resize images by clicking on to one of default sizes ( Small, Medium or Large )
  • Advanced resize - Lets you resize images to any desired size

There is also nice image cropping feature that lets you easily crop out any part from image.

Try it out at http://resizeimage.org/.