... actually you will AUTOMATICALLY be connected to the wireless server with the higher end (G), ONLY IF you are the only person using the network, or if all the other users connected to the network are also connected using a (G) card. If someone were on the network using a (B) connection, EVERYONE is forced to connect with the (B) status, even if you have a (G) card, meaning youll be connected at 11 mpbs. The wireless card will automatically choose the settings; you dont have to.
im not sure how you can check, but try using teh airport client monitor. if it works, you can see the connection rates.