From Slashdot are links to an article from Bloomberg and United States District Court for the Southern District of New York court's decision (PDF) granting the motion for summary judgment, which basically tells BT to go away and forget about such a silly lawsuit.
The case centers on BT's contention that they had a patent that sounded a lot like the internet. ("Sargent Patent describes a system in which multiple users, located at remote terminals, can access data stored at a central computer.") They sued Prodigy as an ISP believing infringement.
An old Slashdot article has further details.