Mobile phones and their networks - what sim works with what phone?

Question

I'm on a contract with vodafone at the moment, and want to keep this sim if possible. I am looking into buying a new phone though, and wondered if I was restricted to phones which only provide vodafone sim cards? If I were to get a pay as you go phone on, say virgin mobile, would my vodafone sim work with that phone? - I dont like the phones available with vodafone at the moment lol. I remember a while ago I put a sim from another network into an orange mobile phone (that was a nokia) and that worked, how can I tell what model of phone my vodafone sim will work in?
I quite like some of the motorola models. Any help here would be appreciated.
I'm looking into asking vodafone for an upgrade, but the last time I did that, the phones they offered seemed to be 'downgrades' from the phone I had!

Answer 1

If you are on Contract with Vodafone wait till your contract is up with them & try getting a new phone from them. Telephone them up to see what date your contract is up. They will give you the phone for nothing & you may have to pay for postage. Postage cost me £6 for when I upgraded from my TMobile contract 2 weeks ago.

Regarding buying a virgin PAYG phone then your sim card will not work in it as they have different settings but you can take the Virgin phone to any shop to have it unlocked for it to be able to be used by all the networks which will cost you around £15 I think it is.