A hospital in Holland is doing research for tinnitus for some time
now,  and has found some very good results so far.
I'm one of the patients in the experimental project,  I try to explain
what I know so far.

They think that tinnitus is caused by high brain activity, they can
see this because of the FMRI scans (Functional Magnetic Resonce
Imaging), this is a different scan than the MRI scan, for the MRI scan
gives a picture of the brain structure and the FMRI gives a scan of
the brain activity. It seems that where you have the tinnitus there is
a big chance you have there a higher brain activity.    

The experimental treatment  they are doing now is TMS,
TMS is transcraniele magnetic stimulation, which means that that they
will put a magnetic spool on the head, what will give an electric
pulse and will reduce the overactive brain activity.

I will go there in 3 weeks and will let you know how it went, but it
seems hopeful.