T-Mobile USA introduced a new unlimited plan today that comes with all-you-can-eat voice, texting and data for $79.99 per month.

Subscribers signing up for the new plan may want to read the fine print: T-Mobile says it will throttle speeds for subscribers who use more than 2GB per month.

The carrier did not provide specific details on how much it would reduce speeds for heavy data users who exceed their monthly limit. The plan will only be offered for a limited time and customers must sign a new two-year contract to qualify.

The carrier’s new Even More unlimited plan offers more data than T-Mobile’s current $79.99 plan, which comes with 200 MB and unlimited talk and text.

“While data plans for many of our competitors continue to be very expensive, T-Mobile is lowering the price of our unlimited plan and offering more options,” T-Mobile marketing executive John Clelland said in a statement.

The company is positioning the plan as cheaper than comparable offerings from AT&T, Verizon Wireless and Sprint.

T-Mobile is working to keep its offerings competitive and retain customers as it waits for its acquisition by AT&T to pass regulatory approval.

In addition to the new service plan, the carrier unveiled its latest HSPA+ smartphone yesterday. The video-friendly HTC Sensation 4G comes with HTC’s new HTC Watch video service and the manufacturer’s highly praised Sense user interface. The Android-based smartphone will become available this summer. Pricing has not yet been announced.