So I was thinking of trying to find a game I can play with a friend when I'm on the train, or have a spare minute at work, or on the toilet. I've got access to a Windows Mobile Phone and an iPod (with Wifi pretty much everywhere) and I'd prefer something cross platform as most of my friends use an Android phone.

What I'm after is a turn based game that doesn't require a constant connection. So a game whereby I can submit my moves, he'll receive it and can make a move back. If we both drop offline then I don't want progress to be lost. I thought chess would fit pretty much perfectly in to this.

I used to play email chess which I guess I could do now, but it's not exactly ideal for on the go (being I'd have to have a copy of the board etc).

So are there any chess clients that allow this? Or any other games that fit the bill.

I've googled but can't seem to find anything that matches what I'm after.

::Edit:: We've been teaming up on Urban Dead, which has been fun, so any browser games like that.