Is it possible to get all your old contacts from the phone you lost on to your replacement phone?
I was told if you phoned orange they would be able to transfer them onto my new sim?

Unlikely, unless Orange have some kind of automatic synchronising service. Do any of the carriers do that?

I signed up to Mobyko a while ago, who do exactly that. As long as you have WAP you can upload your contacts to them and then download them onto a new phone if you need to. I also got money back by going through Quidco

Mobyko also have a cool Facebook app which sends your friends facebook profile pics to your phone too - although it does seem to have a few bugs at the moment.

I think O2 were offering a backup/sync service a while ago, not sure if it cost extra or not, or how it worked.

I just back up numbers on an Excel Sheet on my Computer.

Ditto.

God knows what I'll do if I lose my phone and my computer fucks up at exactly the same time.