VNsea is a graphical VNC client for both the iPhone and the iPod touch based on Chicken of the VNC for Mac OS X. CotVNC is also hosted at SourceForge.
Release notes:
15 Dec 2007 The new version 0.7 is now available for download. This version includes bug fixes and some nice little features. Most interestingly, double-tapping on the system status bar will now switch back and forth between the normal active mode and the view-only mode where you can scroll with a single finger (but cannot click or type). http://code.google.com/p/vnsea/