The sword that Cloud actually used throughout the movie was NOT the sword that he used to defeat Sephiroth in FF7. (That was the Buster Sword, the sword you see at the beginning of the movie where Cloud leaves it as a testament to Zack.) The sword that Cloud uses throughout the movie was First Tsurugi or "First Sword", and the finishing move was the Choukyuu Bushin Hakazan Version 5 or "OmniSlash Version 5", as opposed to him using "OmniSlash" in the video game to finish off good ole Sephie.
All of that and more information is available in this FAQ from GameFAQs:
http://db.gamefaqs.com/portable/psp/...ii_ac_plot.txt
Enjoy.