On Vodafone, unless you pay the full £20/month (in addition to your monthly line rental, which is £10/month at the cheapest atm iirc) you have to pay extra for VoIP and P2P stuff (and their docs say IM too, though the person I spoke to said that wasn't true). Thies does give you an uncapped connection though, while the £5/month add on is capped at something like 500Mb.

Are there any restrictions on the 3 deal, etc.?