if this is broadband.
If it is not broadband but is dial-up, you need to set your Network Preferences > Modem to respond to calls from Mail and Safari for internet access.
I have a new MacBook Pro 13 with OSX Snow Leopard and an Optus wireless USB modem. I have to manually connect to the internet. How can I set it up so that I automatically connect to the net when I launch Safari or Mail?