When will Sprint Nextel's (S) WiMax network get off the ground? Anyone's guess now: The launch has been postponed (again) from this month to "later this year" to work out logistics, a Sprint rep tells TheStreet.com.

What does this mean? With every delay, Sprint is losing some of its early advantage against rivals AT&T (T) and Verizon Wireless, which won't launch rival "4G," or "fourth generation" networks for a few years.

When Sprint first announced plans for its WiMax network in August, 2006, it said the service would reach as many as 100 million people by the end of 2008. That would have given Sprint a 2-4 year advantage on AT&T and Verizon, which aren't likely to have massive 4G networks built out until 2010 or 2011 (or beyond). As delays stack up, Sprint loses its lead.

And each time Sprint's new network gets pushed back, it makes the upcoming "4G" format war between WiMax and a competing technology called LTE -- which AT&T and Verizon will likely use -- more interesting. Or, at least, competitive.

Like today's wireless format competition -- GSM vs. CDMA in the U.S. -- gadgets are likely to work with either WiMax or LTE networks, not both. So gadget companies will either have to choose one technology to build around, or make two versions of each device. A wonky horse race, but one we'll be watching more closely.

See Also: Comcast, Time Warner Cable To Fund Sprint-Clearwire WiMax Venture?