First off, there is NO standard called G4 in the wireless industry. There is a VERY recent 4G technology standard, but that does not stand to be released into a production-ready market for another FOUR years (2010 for the math-impaired) - that is in Japan by NTT DoCoMo. If the North American market keeps pace the way it has for the last decade and a half, expect to see 4G in the United States by 2012 or 2013 (this is assuming that NTT actually has it released by that time).

What Sprint may actually be rolling out, and what Verizon already recently rolled out in their major markets, is the 'upgrade' to 1xEV-DO, called Rev A. This will allow for the theoretical speeds of 3.1mbps downstream and 1.8mpbs return - not much of an increase on the down, but QUITE a bit on the up (although really... is there any need?)...

And as far as 3.1mbps comparing to 54mpbs found in WiFi, I'd have to say that there is no comparison ...at all. And in comparison to the 802.11n WiFi standard, I'd have to just laugh (really, REALLY hard).