With your iPhone mounted on your handlebars you can follow directions and you can keep track of your cycling with apps such as Strava and CycleMeter.
There's a huge variety of bike mounts out there to choose from. Here I'll outline two of my favourites and why I think they are the best.
The Tigra iPhone bike mount is my favourite choice because it is highly waterproof, it safely holds the iPhone in place and you can easily read off the iPhone screen. However, it is quite bulky.
The Topeak iPhone drybag is another good mount. I like how it is less bulky, so it can be stashed in your pocket. However, the screen is sometimes hard to read and you don't have access to the ports.
It's also worth investing in a portable battery pack such as the Veho Pebble as using your iPhone for navigation uses up a lot of battery. This can sit in a handlebar bag and keep your iPhone charged.
Here's a quick list of apps I'd recommend: Bike Doctor - for repairs. Bike Hub - for navigation (UK). Strava and Cycle Meter - bike computers. I recommend more apps for cyclists in my next guide.