Here's the link, One Piece Strong World.
It's split into 6 parts, each around 20 minutes long, and man, the movie is damn good. Enjoy :).
New - Hey guys, I've got two links where you can download the movie and not just watch.
GetBleach - It's a torrent and a bit over 1GB to download.
Anime-Access There's two direct download versions both using the mkv. file type, one's over 1GB as well while the other is only 340MB. I'm not sure if that's because it's compressed or only a part but.......well you guys can find out right? :)