Best way to merge mp4 files

Got a bunch of .mp4 videos (info shows H.264 Video + AAC Audio) that are chapters of a larger video. I'd like to merge them, but not sure which is the best way. I don't have Quicktime Pro, but I'll get it if that's the best way to do this. Edit: Just to clariify this is Mac OSX 10.6 I'm on.