Cellphone weather inflight

I was at the local Altell cellphone shop the other day, and they were
showing me a new USB doodad that you can plug into your laptop computer and
use the internet anywhere they have signal coverage (most of the nation from
the chart they showed me) at DSL speeds. It's aimed at people who are on the
road a lot. Does anyone here have that service, does it work well for you,
and more importantly, does it work inflight? Might be a good answer for
those of us whose GPS' don't have XM Weather capability.
Scott Wilson