[Stuart]

I'm in two minds about apps checking whether your device is rooted or not is a good thing.

On the one hand, I can see the advantages for the company, in that you can install pirate software on rooted phones, and also if a phone is not rooted, theoretically, there is less chance that the user will have installed something that will stop your app working (so, support costs are lower).

On the other, I just think that if you paid for the phone (whatever platform and model), you should be free to do whatever you want with it (assuming it's legal, of course). The likes of Virgin and Sky have no right to know if you are using a rooted phone or not.

Note: My opinions apply equally to jailbroken iPhones.