The NTSB concluded its investigation into AS261 yesterday.
Quote The National Transportation Safety Board determines that the probable cause of this accident was a loss of airplane pitch control resulting from the in-flight failure of the horizontal stabilizer trim system jackscrew assembly's acme nut threads. The thread failure was caused by excessive wear resulting from Alaska Airlines' insufficient lubrication of the jackscrew assembly unquote
The report and related info may be seen here:
http://www.ntsb.gov/Events/2000/AKA261/default.htm