After some searching, I discovered (thanks to Barbarian Blog) that it is possible to get Facebook to update the text excerpt and preview icon from shared web links by going to the following page:
http://developers.facebook.com/tools/lint/
… just enter your URL, and any Facebook entries pointing to the link will be updated with new content.
Thanks for posting this…this exact thing happened to me when posting a soundcloud link just now. Nebula to the rescue
Anything for you, brutha!
Not 100% sure this still works. Anybody in the know care to comment?