Question : advance image editing via the web

I'm looking for an online tool that will edit the attached image without my having to install anything, and 'preferably' allow online sharing of the image from within the site.  it needs to have enough built-in tools to select an appropriate font and font selection dialog should be easy enough to make a decision in.  It must support transparency, allow me to erase, and existing title and tagline to put in something new.

Attachments:

customLogo.gif.png (8 KB) (File Type Details) 

logo change via the web

Answer : advance image editing via the web

new version : GIMP Portable 2.6.9: http://portableapps.com/news/2010-07-04_-_gimp_portable_2.6.9