Wow, this is interesting. TetherGPS solves one of the main drawbacks of Nook Color as a tablet. Being an e-book reader, Nook Color does not come with a GPS installed; so, Navigation services like Google Maps Navigation do not work. But now they will work, thanks to TetherGPS.
TetherGPS shares the GPS data via Wifi network, so connect your Nook Color and your Android smartphone to the same WiFi network, or tether the Nook Color to Android phone with android-wifi-tether. Run TGPS Server on your Android phone and TGPS Client on the Nook color. The Nook Color will receive GPS data from the Android phone. Applications on the Nook Color such as Google Maps and Google Navigation will then work using the shared GPS data.
This is valid for other Android devices as well not just Nook Color. TetherGPS is available for $2.99 in Android Market, there is also a free Lite version but that stops works after 5 minutes.