I went the same route as Captain Chet. (Thanks for the great instruction) and use it with my Nuvi 205W.
When I upgrade to a Nuvi 500 (Waterproof) all I need to change out is the cradle.

 

I have a Nuvi hard wired to my bike that I swap in between my car and bike. Problem is can't hear it and can't see it in sun glare. I fixed all that this week.
Went and upgraded my cell phone and got a Verizon Droid, it has the Google Map with Navagation in it. I paired it with a Bluetooth ear bud ( you need an ear bud with the A2DP profile for it to work on the Droid). Now I can enter the destination put the phone back in my pocket or hip holder or where ever and the directions speak thru the ear bud that I'm wearing and I don't have to worry about getting it wet or anything like that. This thing works great and is as accurate as any Garmin (I tested it against my other Garmins) It works the same as the Garmin units that HD sales that also talk in your ear but cost a heck of alot cheaper. Also the Google Navagation is free not like the Verizion Navagator which cost 10.00 a month. Ya got to try it you won't go back.

 

Here are a couple of photos of the Ram mount on my Softail with the Tomtom One-130. I can see the screen pretty well even in full sun. Can't hear it with wind noise, but it works for me. Going to hard wire the battery tomorrow.