I am using 3 with an x series silver add on £5 month with 1 gig data usage. I got a free nokia 6120 S60 phone which has hsdpa. I have used it with my N800, although sparingly as this is contrary to the terms of the contract. There have been no probs or additional data charges so far. 3 do broadband lite where you can use your mobile as a broadband modem for £10 per month for 1 gig and broadband plus 3 gig for £15.