I'm considering getting an iPhone soon, if the contract prices come down a bit in the UK, with the competition from having it available on multiple networks. Anyone here using any of the cycling apps (GPS or other)? Any experience with the different bike mounts?

Based on my limited experience I would think iPhone would be a rather poor GPS tool for cycling.  First of all it depends upon having a data connection (3G or E) and that precludes me using out of my base country due to excessive roaming fees.  Second many rides get into areas with poor cellphone coverage.  Third, my 3Gs is rather poor at connecting to satellites with Apps like Map My Ride.  Therefore,I would stick with Garmin device if you want GPS.

 There's some pretty good apps for tracking rides. But you wont be able to do any long rides, because the battery on iPhone blows.

I have a 3Gs but I have no plans to mount it on the bike: haven't seen a sleek-enough mount yet and it seems stupid to put something with a glass screen, no shock absorption, and that can't withstand a 2-3 foot drop onto a bike and then fear crashing and being out ~800 bucks. There are a few nice cycling apps out there, google search shows up some reviews and comparisons, but fundamentally, the best use I found for the iPhone is in a ziploc bag in my jersey pocket, to be used only for getting occasionally un-lost, listening to music (using the inline remote/mic on the 3Gs to control everything) and taking calls. It still isn't a bike computer like a 705 is because you don't have ANT capability, and if you want GPS on your ride, just get a cheap Tomtom or Garmin that won't give you a heart attack when your front wheel washes out or a triathlete brakes suddenly in the paceline.

Better hope it doesn't rain while your riding either.

 I own an iphone and a Cervelo and I use both (that may come as a surprise!)  The iphone tracking application for rides eats up power like you wouldn't believe.  Invest in a polar bike computer or something else I'd say. 

HOWEVER - I have been incapacitated before while riding and you can use your iphone to find where you are to tell someone when you call for help.  If you can't exactly walk to the nearest intersection from the middle of nowhere because you've been hurt that is a bit helpful.  (By no means do I imply everyone should buy an iphone for this sole reason though.)

 

Hope that helps - cheers

Love my iPhone and use it for so much. But poor battery life when used for GPS, signal loss in poor satellite reception areas, and an inability to use the phone for most other purposes when actively used as a GPS, stop it being much more than a toy when it comes to navigation/GPS on a bike. I bought a Garmin Edge 705 for this and it does it superbly, but I still take my iPhone on every ride for all the other things it can do very well.

Agree with most of the comments. Sensational phone and the GPS apps work fine - they just annihilate the battery. I've often found myself using Google maps to find my way home on exploratory rides. iPhone - never leave home without it.

I believe that the GPS service doesn't need Edge or 3g to track, it only needs it to display the map. I've been out of service areas, but still had the GPS side of things function.

Take a look at these

http://store.smheartlink.com/

http://smheartlink.com/

 Never heard of an iPhone; what kind of bike is that?