on the adslguide site,
go on compare, and select 6 companies you like the sound of, and it will give you customer ratings in speed, reliability, and customer service.
Then click on List and it will list all the ISP's, the speeds that they can do, and the prices for 512k, 1Mbps and 2 Mbps so you can see who is offering what. Then click on the names yer interested in to see the breakdowns of the prices for monthly, quarterly and yearly and any installation charges etc.
Then go to the forums for the 2 or 3 you have chosen and see what people are saying and ask any questions you have,
I thank you.
Looking at the site, id seriously look at Bulldog communications.....
They are doing....
512 = £289.87
1 Mbps = £349.87
2 Mbps = £457.87
They also come out well on the customer ratings when compared against alot of the larger named companies such as Pipex, Nildram, BT, Telewest and Demon.
Have a look into them mate.