Yes indeed you can
To do this:
Make your first file is ready for the DivX 1st pass, click on File>'Save as AVI' then give your 1st Pass a name (e.g. job1.avi) AND at the bottom of the window you should see an option: '
Don't run this job now, add it to job control so I can run it in batch mode' choose this option and then hit 'save'.
Next make your file ready for 2nd pass and hit 'Save as AVI' again give it a final name (e.g. job2.avi) and check the option at the bottom again. click 'save' and you're done!
What you have done is put those jobs in virtualdub's job-queue instead of executing them straight away. Following these steps you can queue as many jobs as you'd like and then when you're off to school you can have virtualdub batch encode them all.
To do this go to:
File>Job Control (or hit F4) and press Start
That's it!
(P.S. make sure you queue the jobs in the right order, making sure you do pass1 before you do pass2)
Good Luck!