The collection of information useful for biking with a Neo
Secure it to the bike
André Gaul documented a complete mounting kit 
It's just a prototype :) but with some foam around the handlebar and careful positioning to avoid bumps, a basic attachment like this might work  and makes it easy to "pinch" the screen when you need to finger tap something.
Crank up the charge
If you want to keep the GPS running and have the screen always on or staying on with a long timeout, you'll need a way to supplement power.
If you decide to try solar, it's recommended to get a flexible panel and attach it to your backback or something like that. It's unlikely anything below 10 watts will keep things running. (todo: add some data points). One nice advantage here is it might also charge even when you're not moving.
The alternative is to steal energy from the crank. You can do this with a hub dynamo or possibly with an induction generator like the one on the reelight  (warning... overuse of flash)
The regulator will have to be a do-it-yourself project regardless of the power source. See  for one approach. If you do want to try this with a switching regulator, there's a nice little pre-built module in the form factor of a linear regulator that should pop right in: 
Charging via hub
The Freerunner has three different charging modes: 100mA, 500mA and 1A. 100mA seems to be too low, as it is said, that the Freerunner draws 100mA current even when it is switched off. A hub dynamo provides 500mA. If you want to use your lights while charging you need to connect the lights in series to the charger. At least the SON will increase the voltage and still delivers the same current. But you need a bypass circuit in case of less current draw of the charger when the battery is full.