What would I need to greatly improve the range of the N810's wifi?

Would it be possible for my car to pick up a wireless signal from afar and re-distribute it to a small area around the car?

There are now wifi routers available which hookup to a 3G data modem dongle. These would do what you want. Google for 3G router or hsdpa router.

Actually, I was hoping to find a non-cellular solution. I recently canceled my cellular phone service and will be trying out limited mobile calling via wifi w/ skype service. So is there anything I can do to improve my connectivity to open wifi while in my car?

You do realize how wifi works, right? Relatively short range, no guarantee of another "free" access point when the one you do manage to connect to fades away...

I suppose you could just build 360 of these and point them in a 1 degree circle on the top of your car...

That looks cool. I was thinking maybe something a little simpler... maybe a high strength omni antennas in the windshield or some something?

is connecting to open wifi illegal? if it is then my whole phone idea is toast...

As far as I know, it is only illegal in the state of Florida.

but how are you supposed to tell the difference between whats set up for public use and whats just not secured?

I would drop this idea entirely. Connecting to a wireless access point without the permission of the owner is treading on thin legal ice. People have been arrested in their cars outside of establishments using the WIFI.

Secondly I really am hesitant to connect my device to "strange" access points. To many security issues there IMHO.

There is a program where people sign up to share their wifi with other members of a community I forget the name but that would be the best legal option.

Sorry about the remark about Florida ( I was just kidding). Usually I can tell an unsecured public access point by the station ID (SID). If it says Starbucks or McDonalds they expect you to connect. If it has a SID with a router manufacturer name, such as linksys345 then it is most likely a private home that did their own installation and did not bother or did not know how to secure it. As far as legal or not, if your neighbor doesn't lock his front door it doesn't mean you can walk into his home. Our city of Riverside got smart and installed free WiFi throughout the city. No excuses to "steal" a connection.