Update: You can get the Retina Display version here: http://blog.twg.ca/2010/11/retina-display-icon-set/
Lately we’ve been getting more involved in developing iPhone apps for our clients. iPhone apps have their own size and UI standards, so we decided to speed things up for you by sharing some clean and simple iPhone toolbar icons. Feel free to download this 160-piece set, and use it in on your own projects. If you decide to download or use them, please drop a link to this blog post. Thanks!
2009/10/06 Update: We’ve received several inquiries about our iPhone icons. We’ve decided to license them under a Creative Commons Attribution-Share Alike license. You may use the icons for both commercial and non-profit purposes, as well as modify them (in fact we challenge you to make ’em better).