It looks like T-Mobile may be offering up a sweet deal for BBM users soon. According to this internal doc showing some product launch dates, they will be including BBM as part of the unlimited text bundle - meaning those with no data plan can still use BBM with no issues.
BlackBerry customers with Unlimited text and no data will be able to use BlackBerry messenger without charge
This is awesome news if you're a T-Mobile user and I have to say I wish other carriers would pick this up as well. There are plenty of BlackBerry users who don't have data plans and would love to be able to use BBM as part of their text package.
The new service will be added to exsiting unlimited text plans automatically upon launch (which looks to be October 21).