New to gumstix, so please be gentle.

I am looking for a way to connect a cellular modem, preferably 3g but gprs will do for a start, to a gumstix module. Anyone has done this? I see there used to be a line of products called Goliath with this feature but it is eol. 
What will be the best gumstix module to use, and the best ( = easiest to setup) modem device to use with it?

Any hint in the right direction will be valued.

Thanks alot!

 - Arnon.