More than a year ago, when talk of perceived problems with AT&T's wireless network hit a fever pitch online, I was among those who asserted that the performance problems some were having were due to the iPhone, as AT&T had become the first network to have to deal with millions of people using smartphones all the time.

As an AT&'T iPhone user, I say, welcome!

Sure, smartphones had been around, but not in the numbers they hit when the iPhone 3G came out, and people didn't devour data as much as they did once the App Store opened. I blamed the problems mostly on iPhone users, like myself. (And I wasn't the only one.)

That said, if Verizon, as expected, announces an iPhone for its network tomorrow, and, as expected, some AT&T users jump ship for the new carrier, it might actually be a good thing for AT&T--and its remaining users.

Analysts from the Yankee Group estimate that 2.5 million iPhone users on AT&T might migrate to Verizon in the first year due to AT&T's overtaxed network, and that represents about 3 percent of AT&T's 93 million customers (though estimates range from 1 million to 6 million). But those are iPhone users, which use the lion's share of AT&T's wireless data. (Some estimates put it at as much as 65 percent.)

A migration on that scale means AT&T might take a small revenue hit, but it also means that much of the data that those 2.5 million iPhone users eat will be freed up for the other several million iPhone users.

Some analysts suggest that Verizon will sell 13.2 million iPhones in 2011, including subscriber turnover from AT&T, which is expected to sell 8.8 million itself, even with competition from Verizon.

This is all academic, though, as the expected Verizon iPhone is not yet available. There's no telling how many users will switch, though it's almost certain that some will.

One more variable to consider: AT&T's 3G is based on GSM's HSPA, which tends to be faster than Verizon's CDMA-based 1xEV-DO rA. It's possible AT&T iPhone users who switch to Verizon will actually get slower 3G speeds than they had before, which might cause some backlash that could keep some users from switching.

AT&T Executive Vice President Larry Solomon noted the possible difference in speeds, saying, "The iPhone is built for speed, but that's not what you get with a CDMA phone. I'm not sure iPhone users are ready for life in the slow lane."

This was, of course, a way to try to talk up his own network while throwing a slight diss to the competition. But Solomon can't keep that small percentage who are frustrated with AT&T's coverage issues from leaving for what they think might be greener pastures, and that might be OK. Freeing up 3G bandwidth on its network while losing little in revenue is a good thing for AT&T--and its users.