Is there any open source software to load a .MOV video and speed it up? I've got some video of storms that I'd like to speed up 10x.
If you mean increasing the playback speed, VLC can do that. VLC is an open source software for both Windows and Unix/Linux environments.
If you want to create a speeded up version of the video (and not just for a single time playback) you will have to re-encode the video. This is somewhat complicated but you can do it with a myriad of video encoding programs. My favorite is VirtualDub http://www.virtualdub.org/.