The official time is simply the time of your .fcm (I hope you used FCE Ultra to record the movie.) To see your time of your .fcm, open up your ROM, go to "File", and click "Replay Movie..." Now choose your moviefile. You should see the movie's length in that box now (this is also the official time), as well as some other information.
To submit the movie, you first have to login
here using your normal username and password, and then go
here to submit your movie. Before you submit it, make sure you've followed all the instructions on the "Submit Movie"-page
carefully, especially the
rules. Let me know if you have any problems. Good luck! :)
Just curious, how much faster than Walker's run did it get?
Oh, and if you are very unsure about how to do it, send me the .fcm and the comments on the run, and I could submit it for you if you want.