This is the network screen. Here you can see who you will be racing against, what track you are racing on and also choose your bike.
You can 'talk' to the other players by clicking in the box by your name and typing a message. Responses will be displayed next to the other peoples names.
Only the Host can choose the track and actually start the game. Others just choose their bike and wait for the race to begin.
For more information on network games see 'How To Play Network Games' and 'Network Troubleshooting'