I have often mentioned my use of the CycleMeter app when these threads come up but I should point out that I DO NOT use the iPhone as my cycle computer. I use it to capture my route and speed data and have it connected to my Daily Mile account to track my progress. On occasion I have used Google Maps when I was lost. I keep the iPhone in my jersey pocket in a ziplock snack back along with my DL, CC and some cash. I don't reference it during the ride. It's just a data logger. I take it with me anyway so why not use it that way?

I've looked at a bunch of the different rigs designed to turn the iPhone into a cycling computer and my consensus was that by the time I buy the mount, case, accessories, etc. that I might as well buy a Garmin 500 on eBay or even the 705 and have a superior dedicated device.