I'm a little late on this one, but late last week the U.S. Court of Appeals denied Blackboard's rehearing petition. Their only recourse now would be to appeal to the United States Supreme Court and hope that the court miraculously decides to hear their case. As a result, Blackboard will have to return roughly $3.3 million to Desire2Learn, wiping out 100% of the company's earnings for 2008.
This does not mean that the litigation is over. Blackboard is still suing D2L in Canada for infringement of the original patent, and the company has been granted continuation patents (basically revised versions of the original patents) that they could assert.