I have been using my N900 integrated with my bicycle for a few years and it might be useful to spread the knowledge.
There is plenty of discussion on integrating and powering smartphones and headlights with bicycle dynamos or solar for long range touring over at http://crazyguyonabike.com I am using images from that site too.

I have a folding bicycle that I had a Shimano hub dynamo built into the new front wheel, there are several other brand hub dynamo/generators available, they seem to be the most reliable method to generate electricity but they are also expensive both to buy and to have installed. There are also tire sidewall friction generators or bottle generators but these are most useful for when you end up out after dark and need to power lights to get home not for the higher demand of a smartphone.



I use A Shimano hub dynamo to power lights and to run a home made power converter that turns the 6 volt alternating current into regulated 5volt direct current supplied to a USB port. There are several commercial converters from cheap eBay junk to some very good, the price seems to be about $100 and up to get a good converter system.that is tough, reliable, and able to reliably charge in a wide band between just above walking pace speeds to long fast downhill runs. There seems to be a good consensus at crazyguyonabike.com that the best is the German B&M E-Werk dynamo power converter system though there are others.
below are two links to some older pics of my system then one of the e-werk.
http://www.crazyguyonabike.com/forum...pic_id=1181051
http://www.crazyguyonabike.com/forum...pic_id=1181052


I have found that if you are riding a loaded bicycle with camping/touring gear up a moderate incline your speed will probably be too low to charge a phone but enough to power modern high power LED head and tail lights designed for dynamo systems. However if you will be on a good flat or easy hills you will generate plenty of power without actually feeling any additional load.

For reliable phone power running your backlight, GPS, CPU intensive apps, or 3G data where there are moderate to steep rolling hills I usually plug the dynamo USB power directly into a USB battery pod. I have a Yoobao Dual USB port Long March 11200mAh. This can take a charge from the N900's 110/220AC mains charger as well as the bicycle dynamo system, a car charger, or any power source with a microUSB jack. Some of the bicycle chargers especially the E-Werk power converter can be accessorized with a rugged cache battery designed to mount to the bicycle frame but this is not as large a capacity as the Long March battery pod. I have not run this dead yet but it should be good for at least five days at moderate consumption, though the N900 can really burn amp/hours when all the gadgets and CPU are running at full power.



I find that any phone holder system that tries to hold it with a foam or rubber clamp that I have tried doesn't securely hold a phone or GPS and will eventually bounce your phone out onto the highway, probably when you are doing a 70km/h downhill next to traffic. There are some car and motorcycle mounts for the N900 that may need modification or mating to a bicycle handlebar clamp to hold the phone securely but there is still the issue of weather, I have not tried any of these and cant comment. I ended up getting a universal GPS/phone waterproof enclosure that was a bit large for the N900. I made a tray from chloroplast (like cardboard box) sheet form an election sign that I cut and secured with hot glue to center the N900 and made an area on one side to hold the charge cable safely. This phone holder has a soft plastic touch screen cover that lets clumsy touch finger interaction but keeps the weather out, there is also a weather resistant port for a power/charge cable. The waterproof holder had a bicycle handlebar clamp and quick release connection to the actual phone enclosure which broke, I secured the enclosure itself permanently to the handlebars with zip-ties through the vents on the back which works fine.



Since the phone is inside a weatherproof capsule I interact with it using the touch screen and a modified Nokia BH-214 Bluetooth multimedia headset with a 3.5mm stereo jack for headphones. The BH-214 comes stock with a battery good for 6-7 hours of music or talk. I replaced the battery, which I describe in another post, with a battery good for about 24 hours of audio or talk. if the weather is good I attach a large safety pin to my collar and clip the somewhat flimsy clip of the BH-214 to my collar. If I suspect rain I will stick the BH-214 in a sandwich bag with a rubber band around a longer set of headphones to keep it dry.



Here are some quick links I found web searching for the things I mention in this post:

This is one place that sells the USB battery pod:
http://www.xengadget.com/products/21...filiateid=1008

This is what many consider a great dynamo power to USB converter, I want one:
http://www.starbike.com/p/Busch-M%FC...RK-361-3707-en

This is the weather resistant phone enclosure I am using:
http://www.amazon.com/Navitech-Water...284712-4490337

If you want to see what a hub dynamo looks like or some of the friction powered alternatives visit the Peter White Cycle Shop site linked below, it has plenty of info and pictures about dynamo lighting and power systems. He also is the exclusive importer/distributor to the USA for many of these German systems and components and charges a serious markup for them so prices of dynamo systems if purchased in the US vs the UK/EU are sometimes very high so shop around, see starbike.com link above. http://www.peterwhitecycles.com/