Will New Phone Networks Hold Up?

What if you didn't finish building it, and they came anyway? Some of the country's biggest cellphone carriers may be about to find out.

Verizon Wireless, AT&T and Sprint Nextel have spent billions of dollars rolling out new networks that promise super-fast speeds for browsing the Web on mobile phones. And they have heavily marketed the technology, called LTE, even though for AT&T and Sprint those networks aren't anywhere near complete. That hasn't been a problem so far, because only a small percentage of their subscribers actually use the new networks. But the coming iPhone 5, which touts LTE capability, may tempt the masses to try those networks out, exposing gaps in coverage and testing the networks' ability to handle heavy traffic for the first time.