Just dropped my iphone 4 in the sink?

I got it out very quickly but it turned it self off. I've not tried to turn it back on yet, i've just put it in a bag of rice and put it on the radiator. Has anyone had the same problem? And do you have any suggestions please?

You can get a save-a-phone bag

Leave it as it is for 24 hours it has a Good chance of being ok but first take the battery out and dry it on its own

I think the best way to solve your problem is to disassemble phone parts, so they can dry. I've had the same experience and it started working two days after it fell into the pool. Although, if it doesn't work take it to your phone company, they know the best.

You didn't say if you took the battery out - that's #1
#2 is be careful about the radiator (and blow-dryers) - heat can damage electronics. The problem with blow dryers is that, even on air only (no heat), the air can push water further into the phone.
The rice (or a bunch of desiccant packets, like you find packed w/electronics and the capsules in some medicine bottles) is a good move. Here's a complete list of dos and don'ts w/illustrations:

http://www.wikihow.com/Save-a-Wet-Cell-Phone

The battery doesn't come out on an iPhone (easily). I suggest leaving it in there for 2-3 days. Also silica gel packs (the things you find in luggage bags) helps too.