There are Mac users within empeg, who seem to get on with JEmpeg OK. Last time I looked it came fully wrapped in an installer complete with JVM so it shouldn't be too hard to fire up. If you have problems email
[email protected] as he may be able to help (he's used it on a Powerbook).
Sorry for the lack of native Mac support. We don't have any Mac programmers here, but we opened up the sync tool source to encourage others to develop for other platforms. We weren't expecting the Java solution, but it's rather cool.
Rob