If you mean Andreas Hofer's Planetarium there is nothing equivalent that I have found on the web, and certainly nothing for the iPhone. Which is one of the reasons I still have a Palm TX in addition to the iPhone. (Some of the other reasons are Documents to Go, Worldmate Pro, AvantGo, MetrO worldwide mass transit routing, Bonsai outliner, Project@Hand, Pleco Chinese dictionary, HanDBase, Vindigo, Zagat to Go...) In many ways the iPhone has a long way to go to catch up to Palm.
best,
Larry