anyone done it ? or had experience of it ?

ideally, i want to do a straight swap of my blackberry curve 8520 (unlocked) for an iphone 3g or 3gs, but i guess i've only ever used ebay for getting rid of stuff.

Funnily enough when I was selling a spare Desire HD on eBay I had a couple of offers from other members asking to swap it for an iPhone 4. I refused obviously, but it appears the swapping offers are on there if you have something that someone else wants instead of what they have.

I just did a quick Google search for 'swap your mobile' and there were a couple of sites that popped up. I've not tried them, but Google may be a good place to start for you

It might be an idea to put it on ebay as a listing and see what offers come in. I know an online trade is full of potholes so I wouldn't even consider it unless I was fully satisfied that i'd get the right outcome.

I've seen a few of the trading sites as well,but i think i'll probably give the ebay route a go first. cheers

There's one here for different things,don't know if it's any good tho.
http://www.sheffieldforum.co.uk/forumdisplay.php?f=127