@Liver_Diver
I can also say that I've had a great experience with Virtual Landline. If you cancel your number they will 'quarantine' it for 6 months (I think) and you can resume it if you wish. Also they don't charge for porting your number in, apparently it's included in your 1st months charge. Personally I wouldn't go to any VOIP supplier who doesn't have a rolling monthly contract - if they're rubbish they're easily dropped.
If you want to use your own equipment you'll need to contact Virtual Landline for the password etc. In my experience they answer queries very rapidly by email.
There are couple of downsides though. Numbers like 101, 111, 1471 etc don't work. This may well be the case with other VOIP suppliers although I think the '100' numbers do work with A&A.
I did look at Vonage [briefly] and decided to keep away after reading their reviews. I wouldn't go to TalkTalk for much the same reason!
