Yackie is probably the one you are thinking of.

www.yackie.com

No experience with them. I'm looking at places like

www.yackie.com
www.rangeroamer.com
www.united-mobile.com (which is where riiing is based now)

and a couple others for a few trips coming up.

Make sure to look at all the small print, one minute vers six second billing,things like that make a huge difference in total cost, it's just not a per minute rate