A: Do this using Quicktime Pro. Just open the first movie, then drag the next one into the same window and so on. You can now reposition the clips in the order you want.
You can also trim the joins if you need by pressing ⌘ T and then moving the trim selection tool accordingly.
Once completed editing, export it all as a Quicktime movie or any of the other formats that Quicktime supports (usually exports as m4v or simply use the "save as" option).
Q: How do you join mpeg files?
A: Using iMovie import both mpegs, then lay them both out in the timeline as desired. Then export (or share).
Also, iMovie does like to export in Quicktime format, but you can export in any format, pretty much. Here's how:
When you are finished ordering the mpg's in iMovie, go to File > Share...
From here, click on the Quicktime tab, and in the selection box, select the Expert Settings at the bottom. This will allow you to access the full Quicktime encoding library.
From here you can encode in pretty much any codec you want. MPEG1 is a little dated, so you may want to explore the newer codecs, like Mpeg-4 or h.264.
Q: How do you join vob files?
A: Navigate to where the vobs are using Terminal (e.g. cd:> to the desktop) and type something like this:
cat vob1 vob2 vob3 > reallybigvob
...obviously change "vob1" etc. to the exact name and name the resultant vob whatever you want.
