Blueman is a GTK+ bluetooth management utility for GNOME

If you need simple tol to manage your bluetooth in Linux
Blueman can help you - http://walmis.balticum.lt/



One of the features is network connections manager.
you can connect to internet using your PDA or another PC via bluetooth in few clicks.

If you are looking for script nased solution try the following script:

modprobe bnep                                                                   
pand --connect 00:17:E3:7F:06:CF --service NAP --autozap                        
sleep 7                                                                         
ifconfig bnep0 192.168.0.2                                                      
route add default gw 192.168.0.1 bnep0                                          
echo nameserver 192.168.0.1 > /etc/resolv.conf