One of the many pains of Blackboard is that once materials have been placed there, it’s a royal pain to get them back out.
Uncle David Moffat has tackled this problem and come up with bFree, a course content extractor. This Java-based software has been tested and runs on both Windows XP and Mac OS X. No word on Linux support but since it runs under the latest Java Software, there is a good chance it will.
Read about bFree and download the software here (Creative Commons Attribution-Noncommercial-Share Alike 2.5 License)