If you have recently bought a 4g device, whether it be a phone, or netbook, or whatever it is and you can not get a 4g signal, you shouldnt be so suprised. Companies like AT&T, Sprint, and Verizon wireless are putting alot of hype on these 4g devices, but the truth is there is more marketing than there is technology behind this. From watching all these commercials about the 4g network one would think that you could go out and buy a 4g device, turn it on, and you are automatically operating on the 4g network, this isn’t so true.
Truth is the 4g network is nowhere near nation wide yet. As of right now Sprint offers the most 4g in 70 markets through 17 4g phones and netbooks. AT&T on the other hand is just starting to actually roll out its 4g network and plan to go nation wide with it in mid 2011. Verizon last month stated that it is operating on the network in 38 metropolitan areas.
for more info on 4g check out: http://gcn.com/articles/2011/01/13/what-is-4g.aspx