AviStack is a freeware to register, stack and process astronomical movies and image sequences. Primarily developed to process lunar images, AviStack has also been used on processing solar and planetary photos. The software is fully compatible with The Imaging Source astronomy cameras.
There is a Group about AviStack on Yahoo. In that group, users and experts discuss the their experiences and exchange tech info on this tool. For instance the software's developer Michael Theusner put out a note on 05.July recruiting people to test and report bugs of the Alpha version of the up-coming AviStack 2.0, and the response has been phenomenal. The testing had closed on 09.July. Michael has been crazy busy with it afterwards.
Have fun and clear skies!