I have a 7100t with Cingular. I'd like to connect it to my office LAN (not use
GPRS) occasionally. Is there an application which would allow the USB port on the Blackberry to be used to route IP data to a PC which would then route the packets on to the LAN

There's the HandHeld Manager that comes with the Desktop Manager 4, but this is to connect to your BES through the ethernet instead of through the wireless, I don't think this is what you are looking for?

I actually want to access a LAN or Wi-Fi hot spot directly with the Blackberry for situations where thats the only device I am carrying - i.e. no laptop. There are USB to ethernet and USB to 802.11b/g adapters - however one would need to write a blackberry driver to make this happen

I hope you have a little patients;
Check out the BlackBerry 7270 Wireless Handheld for Enterprise WLAN
It might just be what you are asking for.

There are no blackberry's that will handle both gsm/gprs and wifi right now. Other than using your data cable and desktop manager there isn't a whole lot more you can do.

cd.