Well the movie has been subbed by Ena&Enm -
Enm@irc.irchighway.net
The file is fairly big at 1.12Gb but it is 1:33 mins long so if you think of it as 4-5 episodes it makes sense.
I've watched and think its really good and well worth the download.
It doesn't fit in anywhere in the story but instead starts from the beginning and tells the story differently but with some similarities
Anywhere heres the link:
Clannad the Movie
ps. il probably split it up into parts in a while.