Cellular Connection for Asterisk via US GSM network

I?ve been looking through the forums and I?ve not found an answer to this question, so I thought I would post it.

Is there a way to connect my humble asterisk box to the cellular networks so as to use that connection as a trunk (i.e. make and receive calls)? What I have found is sketchy at best and I was hope for some clarification. I am hoping to connect to the GSM network(s) here in the US.

I have seen some commentary on using a fixed wireless terminal. This is a separately powered device which would then connect back to my asterisk box via my existing zaptel card. The down side here is it being a separately powered device and having it takes up an FXO port. These units are also somewhat costly (for what they are).

I have also seen some (less) commentary on using a GSM PCI card from Junghanns.net. This device seems ideal for what I want to do, but I have not read where it has been successfully deployed here is the US. I have concerns about frequency compatibility. Is there another maker of cards such as these and if so who and do they work on the awkward US GSM band?

There is also a glut of cheep ($130 range) pcmcia GSM/GPRS, I think they are commonly referred to as ?Aircards? or ?Air Cards?. This also seems like a solution, but can asterisk make use of voice on these cards?

Any insight would be most helpful. Thank you.