As a priest, You can cast levitate on a mount so you can run over water.
All it's about is timing.
Simply cast Levitate at about .20 sec, and you'll mount, and levitate will cast right after you mount.
I don't know if it works with a flying mount, but i don't think it would matter anyways
Video
[ame="http://www.youtube.com/watch?v=s71guKIfvss"]YouTube - WoW Emu Exploit Levitate on a mount[/ame]