What is a good iPhone app for cyclists?

I want an iPhone app that tells you how far you have biked. Maybe some extra features like avg speed or a trail locater. If you can please write next to the name if it is free or not

You don't need an "app". You NEED a good bicycle computer. Even the most basic models will tell you current speed, max speed, average speed, exact time of your ride - down to the second - a pace arrow… Whether you're going faster or slower than the average speed, etc.

More advanced units have a "cadence counter" - pedal rpm. Some units will read only your current cadence. Others will read out current, max & average cadence.
http://www.amazon.com/...000N3WP8Y/

Still other units have a temp gauge & cadence.
http://bontrager.com/model/08864

Forget the iPhone. Want to keep track of how you're doing? Get a good cycling computer!

Cateye Strada Cadence Bike Computer
http://www.amazon.com/...000R6QR2C/
http://www.cateye.com/en/products/detail/CC-RD200/

For local trails, just search (Google) bicycle trails with your city or zip code included.

Robert

Leave your iPhone at home. If you take it, use it for emergencies only. Instead, by a wired, or wireless cycle computer. Get one with cadence. It will be a far more valuable tool than an iPhone app. It not only does what you are asking, but helps you train to, be a better cyclist as well.

Http://ipod.about.com/od/bestiphoneapps/tp/5-Great-Gps-Cycling-Apps-For-Iphone.htm