(I'm not sure if this is an Ubuntu or an Android question - feel free to move it!)
Is it possible to connect my Android Jelly Bean phone to my laptop using bluetooth so that the telephone can use the laptop's internet connection?
Android --BLUETOOTH--> Laptop --ETHERNET--> Internet
I'm running 12.10, the laptop has bluetooth and I've been able to pair the two devices.
What you are looking for is "reverse tethering".
I dont believe it has been done through bluetooth yet, but there's a solution that works well if you are willing to connect your phone with usb.
Find all related software and documentation here:
http://forum.xda-developers.com/showthread.php?t=1371345
Please try this: Internet connection sharing from PC to Phone over Bluetooth.
I would've suggested as duplicate but I can't comment yet.