3 don't offer an unlimited tarrif, do they? Internet tarrifs on 3 appear to cost a minimum of £15/month capped at 56Mb/month.

T-Mobile do offer unlimited 3G (also with HSDPA) access, it's called Web'n'Walk Plus for £12.50/month and T-Mobile probably have better national coverage than 3.

If you know a better (pay monthly) deal on 3 I'd like to know!

My current plan is to switch to T-Mobile when the Nokia N95 arrives (hopefully April) - I'll be transferring my O2 account to T-Mobile on Flext25 £25/month voice tarrif along with Web'n'Walk Plus £12.50/month.

I could save £5/month and go with the standard Web'n'Walk, but it's against the Term&Conditions to use this tarrif with a laptop (ie. not allowed to use the phone as a modem with the N800).