First, thanks for the post and to all who have contributed since!
Adding... I had numerous problems getting sakis3g just right on my Pi, from crickets at sakis3g.org to compliation problems. This post (http://insembedded.wordpress.com/2014/03/27/setup-3g-on-raspberry-pi-using-sakis3g/) fixed all that.
But then I kept getting connection failures from within sakis3g. So, I scrolled back to the top and started over with a powered USB hub, rather than directly connecting my dongle to the Pi. That worked! Never underestimate the power of power. 🙂
But... introducing the hub sort of shot my mobile project in the foot. I was trying to use a relatively old AT&T USBConnect Quicksilver device that works great on my laptop. But I suspect that it something of a glutton. So, I'm wondering if anyone has found a "low-power" 3G/4G dongle that works off of Pi power?