http://www.picnik.com
Has a variety of different tools. My favorite site!!!
http://www.fotoflexer.com
Focuses more on making you look amazing.
http://photobucket.com
Holds and edits photos-mostly simple things.
http://www.blibs.com/editor
A veryyy great site. Has a TON of different things. Focuses mainly on animating. 2nd fave site.

If you were looking for some software to download for free...
http://www.gimp.org
It's like Adobe Photoshop -does the same things- but it's free!! & it's not a virus or anything. Very good quality.