Is there a monitor to check broadband usage for BT Broadband

This may have been covered already but would like to know!

A friend of mine has recieved a warning email because she used 5Mb over the Standard package of 10MB twice. She has now upgraded to More Broadband package of 40Mb usage, but would like to know how she could monitor her usage.
Any suggestions welcome.
Jumped the gun
Edited: Found it here http://bt.custhelp.com/app/answers/detail/a_id/32952...

Edited by deleted (Wed 16-Jan-13 01:03:05)