GSM test kit for the USA

I am going to install an RTU and HMI system in Europe that will use GSM modems to transmit the data. I would like to test the system here in the US before I go to Europe. Can anyone recommend a GSM test kit I can use here in the states to mimic the European GSM standard?

Roger W. Harte
EWA Technologies, Inc.
Suite 500
13873 Park Center Rd.
Herndon, VA 20171
http:// www.ewatech.com