The iPhone Webclip Manager will let you easily add a "webclip" icon that iphone/ ipod touch users can use as a bookmark for your site.
Have an iPhone or iPod Touch? Wonder how all those sites have a custom bookmark for the homescreen? Well wonder no more and get your own custom webclip icon quickly and easily. With this plugin you can make a custom icon for your wordpress site or your wordpress multiuser site (yep this plugin will allow each individual WPMU blog to have full support for custom webclips).