It looks simple enough and in emergency situations, this can be a life saver.
Of course in due time, ATT and T-Mobile are likely to come out with tethering plans that may make this unnecessary. However, being the cheap bastards that we are and the shape the economy, this might be something interesting to consider.
I've got ATT DSL so I can access ATT's hotspots at Starbucks but I found myself out of luck whenever I visit Borders because they use T-Mobile's wi-fi service.
Anyway, this should be pretty use for all mobile warriors.
Note: I wonder if someone will simply this even further.