Detect iDevices and exchange information

I would like to develop an application on iPhone, iPod Touch and iPad which will be able to:

• run in backgroup
• Detecte other iDevices which are close to the iPhone
• Exchange information with these devices

I do not know if it is better to use wifi or bluetooth in that case but what I would like to achieve is to have something which does not require configuraion (bonjour?)

Thanks in advanc开发者_StackOverflow中文版e for your ideas and pointers.

Regards,

The Bump API is great for this: http://bu.mp/api

But I suggest you to take a look at this tutorial: http://www.devx.com/wireless/Article/43502/