I'd be interested in this geohash application for the iPhone. How far along are you? Would you be willing to release the source for it? I'd definitely love to contribute.
It's fully working now, just I haven't added the functionality of selecting different graticules other than your own and different dates. Right now it works only for today's stock price (or last open date) and your current location. I will figure out the release specifics in June sometime. Right now I'm under an NDA so I can't release anything or show anything off yet. But it'll be released ASAP.
 iPhone app
Does the app calculate the nearest geohash or the geohash within your reticule? I live at the vertex of four graticules and would like to quickly check the closest meet up point. Thanks for the app!
- I didn't finish the app, another developer did the released version. You can contact him via this website: http://www.kckd.org/geohash/geohash.html