Here is my first GPS tracking using these products, all in all pretty simple to use...
http://www.everytrail.com/view_trip.php?trip_id=581779Well, I have had the Iphone for about a week now, installed the
"Everytrail" app and I have to say I love it.

OK, it's a new toy and I will most likely burn out on it in a month or so... but for now it's great fun. The every trail software is pretty nice and allows you to take pictures inside the program and when you upload the info to the site it tags the pictures location and will do a slide show of your trip. Also you can switch the web site map to statistics and it'll show a little blue dot traveling along your route... very cool

About the only thing I can complain about is on the web site the picture and even worse is the speed/altitude graph pops up and completely blocks the map... ummm make it a separate window or something there folks?
The software also works on other GPS phone so you don't have to have an Iphone 
It works reasonably well and is pretty accurate, even when not getting a satellite signal. From what I understand it has the "turn by turn" setup where if you aren't geting a sat signal it will guess where you are going, I had mine in a camera bag and that inside a seat bag and it was damn close. I understand that it uses the motion sensor like any other GPS but also triangulates off cell towers to keep it accurate? Don't know how true that is but it seems to work.

The Iphone is pretty cool as a whole, little scared at first that I would brake it but some friends over at CLIMB recommended that I get this
"OtterBox" case... well this thing is friggin awesome super over protection. Even the screen has a pretty darn thick clear cover that you can still work it through, though I do notice it looses some sensitivity but well worth it.
One thing to note that I wish I knew when I got mine...
the cheaper 3G only phones don't do multi tasking like the more expensive 3GS phones.. sooo If you get a call or something while tracking with the GPS you need to restart the tracking software. Not a biggy if you remember but could blow a whole ride's output if you don't remember to start the tracking up again.
Everytrail App & Web site I give a 4 outa 5 I'd give it a 5 out of 5 if they fixed the over sized graph window covering the map
the Iphone I give a 4-outa 5 also... I shouldn't have to get a large drive, overly priced, phone just to get multi tasking on an Apple product!
The Otter Box Defender case I give 5 out of 5 thing is just rugged!! and has already save my phone.

comes in a few colors and has cases for Droid and other popular phones
EveryTrail web site,...http://www.everytrail.com/Otter Box Defender Case