It was inevitable.
AT&T was the first to officially move away  from unlimited smartphone data plans to a tiered system. That move aroused a ton of ire among techies: AT&T didn't just add tiered pricing, they eliminated the old unlimited plan. Of course, a lot of that is a gut reaction to the elimination of what we may come to see as the golden years of data pricing--the vast majority of customers (98%) will actually save money under the new plan.
That's not to say that having the unlimited option taken away isn't a bummer. For a select few customers, data bills will go way up. But that's just the way things are going: carriers need tiered plans so their networks aren't overloaded.
Verizon was actually the first  to note that tiered data plans would be the future, but all chatter since has been unconfirmed. Now, Engadget hears  from a reliable source that Verizon intends to hop on the tiered bandwagon by the end of this month--just a week and a half away. It's logical to expect the pricing to be somewhere close to AT&T's, if not identical (200MB for $15, 2GB for $25), although Verizon's superior network might allow a third unlimited option for data-crazy users. It's still not confirmed by Verizon, but it's not unlikely that the company would make an announcement soon.
We'll keep you updated if and when Verizon announces the change.