Broodie,
My understanding of the arrangement with AT&T is that it's 'unlimited' I pay the $30/m. Brian POUNDED AT&T's network for his 'torture test' found here:
3G iPad’s ‘Unlimited’ Data Plan Survives Torture Test | Gadget Lab | Wired.com and it seemed fine!
That said, I've not gotten the bluetooth working yet so calls are on speaker phone. But it works beautifully! It's truly handy to have. If you find a way to get bluetooth working let me know!
I'm interviewing the developer of the WeePhone today and I hope to get some insight from him. Your bike set up looks amazing!
I'm now interested to know how much data is passing during a call. I may have to look into that. Possibly I'll write an in-depth review of my calling solution and will point out the good points and the bad points. It may help a future app developer in knowing what the market is seeking.
Hope that helps,