Frank,
If BT Broadband isn't available in your area then the chances are that you won't get it through anyone else either.
BT still own most of the exchanges where the ADSL (broadband) equipment is housed, and it's these that get upgraded. Tiscali will supply you with broadband, but on condition that you have a BT phoneline which can be upgraded to ADSL. All they're doing is repackaging the BT Wholesale service with their own brandname, and a few quid on top...
Have a look at
http://www.adslguide.org.uk/ for info about broadband. This has some helpful links and FAQs so you should be able to find out what's available and compare prices.