Oooh, do tell more. How do you do what you are suggesting?
Navigate to your iMovie HD project in the Finder. Control-click the project icon to open the "contextual menu options." Select "Show Package Contents" to see the files/folders contained in the project package. Open the "Shared Movie" folder. Inside you should see an "iDVD" folder. Opening it you will find the "Project_filename.mov" that represents the currently saved contents of the the project's timeline to include titles, transitions, effects, etc. (This is the data that would normally be sent to iDVD if you were going to burn a DVD of your finished project.) Simply copy the file to another location or HDD so it can be imported in its entirety to iMovie '08.
NOTE: Never tried moving/removing this file from the package as I thought it might have the potential to corrupt the iMovie HD project and am in the habit of working from work/backup files in case there is ever a problem. (I.e., just don't like restarting from scratch if I can avoid it.)
