Many thanks for all the replies! I'll start checking the options out in the next few days.

It's an 'introduction to web design' course for complete beginners, so I wouldn't even cover asp, php, etc (except to explain what they are) - just the basics of putting a simple brochure website together, and taking them through the html code that's generated, using stylesheets (for font styles only), etc. It would just give them a small flavour of what web design is about, give them a starting point to play around with.