I've been cutting a series of 30 second promos (17 total) that I want to author to DVD. I want to have four items on the main menu, each with a submenu of 3 to 5 sequences. I'm going to cut together the sequences into 4 longer sequences with a second of filler in between each promo. I'm using iDVD, which doesn't have the capability to put in chapter markers, but if the markers are already there, it will set them up. Is there some way to add chapter markers in MC? (i.e. - locators?) Or do I have to import the project into iMovie to add the markers, then export to iDVD?

http://community.avid.com/blogs/training/archive/2008/07/21/how-to-add-chapter-markers-in-sorenson-squeeze.aspx

You can use Sorenson Squeeze.

You can add a chapter track to a quicktime with a relatively simple text file.  There are a few tutorials for this on the Apple Quicktime website (or there used to be).

I have a cheeky filemaker database though that turns an exported text file of Avid locators into such a list.  If you get stuck send a locator text file to me and I can run it through.

Good luck.