This site offers you a practical (and free) way of editing icons online, as well as including an icon collection that amounts to more than 12,000 icons that you can ready look up and employ should you find one that picks your fancy.
The editor takes up most of the opening screen, and all the usual features and functionalities that one expects to see in a tool of this kind are fully accounted for.
Moreover, note that you can create animated gif icons in addition to collections of icons to showcase and promote your work.
The latter feature is only available to those that have an upgraded account. These accounts also let the user add comments to the icons that he uploads as well as drawing images at a higher resolution. Paid accounts also come with enhanced undo functionalities.
As regards the supported browsers, these include both Firefox (version 3 onwards) and Safari. No version of Internet Explorer is supported, and the team might like to reconsider that as it would keep them from reaching a significant portion of public indeed.
Iconfu.com In Their Own Words
“Iconfu is an easy-to-use free online icon editor, combined with an icon collection of over 12,000 free icons gathered from open-source collections around the world.”
Why Iconfu.com It Might Be A Killer
It makes not only for creating appealing icons but also for sharing these with others at the same time.
Some Questions About Iconfu.com
How much do the paid accounts cost? Are the advantages these provide reason enough for people to upgrade to them? 
