Does LETU Have Blackboard Mobile Learn?

Yes. You can check whether any university has the Blackboard Mobile app by plugging in the name here on Blackboard's site.

If LETU Has Blackboard Mobile, Why Does It Give Me A Licensing Error When I Try To Use It On My Android/Blackberry/Apple phone?

There are two tiers of Blackboard's Mobile Learn app: a basic and premier tier. LETU is currently subscribed to the basic tier which precludes the ability to use certain phones when not on the Sprint network based on Blackboard's licensing agreement with Sprint. Essentially, all phones work over both carrier signal and WiFi if you're using Sprint with Blackboard Mobile. However, if you're not on Sprint, various restrictions apply. The most current article on their new licensing agreement can be found here.

This also means that WiFi-only Android tablets cannot currently use the Blackboard Mobile app. 

How can I get the Premier (Paid) version of Blackboard Mobile?

Blackboard will be offering the full version of the Mobile app through what they call the Personal license, for a small fee: $2 per year, or $6 unlimited.  For more information, visit Blackboard's Mobile Learn FAQ, here.