Half the fun of digital photography is in playing with your images when you've got back and uploaded them onto your PC. You have a few choices - most of the photo editors you can buy will have various filter and special effects options. Or you can use an online editor, some of which have some cool effects. Flauntr in particular.

But if you want to go the whole hog and really play with your image you'll need something a little more 'specialist'. Enter Photomatix 3.0. It's just been released and you can download a trial version for free.