John Hunter has put together a list of 17 OA journals in engineering. I haven't checked to see whether they're all alread listed in the DOAJ.
Posted by
Peter Suber at 10/19/2006 11:11:00 AM.
The open access movement:
Putting peer-reviewed scientific and scholarly literature
on the internet. Making it available free of charge and
free of most copyright and licensing restrictions.
Removing the barriers to serious research.
I recommend the OA tracking project (OATP) as the best way to stay on top of new OA developments. You can read the OATP feed on a blog-like web page or subscribe to it by RSS, email, or Twitter. You can also help build the feed by tagging new developments you encounter.