There are a zillion threads about this if you had bothered to search/look through older topics.
The short version:
The iPhone will likely launch in Germany/France/UK before the end of the year, and it will probably be the current EDGE model (although, of course, it would be much smarter to launch with a 3G model). Roll-outs to smaller markets and a 3G iPhone will probably be in 2008.
Nobody knows the providers. In the UK, if I recall correctly, only Orange has an EDGE network, but there are rumours that O2 will spend the money to deploy EDGE to get the iPhone (we'll overlook the fact that the seventy million odd pounds this will take could buy you a 3G custom built iPhone).
The iPhone will likely cost the same as it does in the States, counting the currency translation, plus around 10% or so given Apple's usual mark-ups overseas (Canada gets a discount, sometimes, everybody else gets hosed). If it is instead a 3G model it will likely be a hundred plus dollars more expensive.
Around six months after launch, depending on the country, Apple will legally have to allow SIM card transfers. This does not, however, apply to any multi-year contract you may be stuck under. So your iPhone may be transferable, but you'll still have to buy out or keep your current contract.
The shorter version:
Originally Posted by Ireland
€499 O2, Vodafone, and others. October.