HTML (Hypertext Mark-Up Language) is used to create web pages. IT Education Services offers workshops on web publishing, including HTML. See the IT Education Services page for details.
Another resource is the Knowledge Navigation Center at U-M's Graduate Library. The center offers one-on-one instruction for people just starting out at making web sites.
There are also lots of resources on the web you can check out. Here is just one example: The Bare Bones Guide to HTML by Kevin Werbach.