Actually girl15 is wrong. with the right combination of devices this is possible. I do it now.
The best LAN access USB dongle currently in My opinion is a Linksys USBBT100. It is a class 1 device with all the range you should need. This has the needed software too to provide LAN Access - NOT PAN
My dongle has been outfitted with a TERK Wifi 0 antenna to boost it's range to well over 1300 feet. Parabolic reflector has yielded results of nearly 1.4 mile range with an 11db Dipole and Reflector.
My Laptop shares it's wifi access to this USB bluetooth dongle. I have this paired with my TREO755p and also did this with my TREO650.
Setup for my device to do so... TO pair, USE the connection for LAN, and then SELECT it over the VERIZON network on my phone.
End result- I get full speed 700k. 700 feet solid access radius around my antenna.
Anywhere I can get Wifi with my laptop I can get BLuetooth Internet to my Phone
I can slingbox, bluetooth commander, Mundu IM, Skype, EMail, Surf, Pocket tunes, Coreplayers Youtube. Beeline TV. etc etc.
I rather take my treo to my hotel bathroom than the laptop anyday. with this I can even usually use my phone in the lobby, lounge dining area while my laptop is in my room.
I've set XP up to use the provided bluetooth stack and not Microsoft or this would not work after XP Sp2 ( this is not tested in Vista )