Picnik

So apparently not everyone has photoshop... feeling your pain...
If you are one of those unfortunate peeps, then you might be interested in Picnik. It's just a beta at the mo, so some of the functionality is missing, but basically it allows you to edit and amend your photos online using the glorious technology of Web 2.0. Even if you have got photoshop, Picnik has some big advantages primarily it allows you to edit photos that have already been uploaded to Flickr (without downloading and re-uploading), saving a lot of time and hassle.