After getting my iphone unlocked can i use any sim?

I got my iphone unlocked ages ago and have been using tesco pay as you go ever since. But now I want to get a contract with Virgin Media. I was going to just get a sim card from them but will it work in my phone?

Yes you can:-)

Unfortunately you can't use a virgin mobil sim because they don't use any since there network is CDMA. When an iPhone is unlocked it only works on the gsm network around the world meaning carriers that use sim cards. There are other alternatives to virgin that use sim cards just pick a decent service in your area.

Yes, if unlocked it will work.