Some themes for WPMU seem to allow user customisation such as changing header graphics/colours etc.
How well do these actually work? I'm putting together a site and I've got about 20 themes from Farm's Big Pack that I'm happy with but at the moment they are all "static" which means the user can't change anything.
Pick some and try it.
There's other theme packs floating around and some themes in there have options pages that the hubby & I wrote. I *know* they work.
The latest codebase also has built in the function for changing headers on themes, You just need to add it to the theme (please search)
the only theme you have to watch out for are ones that were built using Ohz's theme thingy, unless he's updated. I know someone did it for MU, but I can't remember where it is. Otherwise, they work quite well.
Alos, if you search, you'll find the repository for wp.com themes, soem of which have customizable headers in them (I think).
Custom header images and colours are usually done via the custom header API.
Tarski uses it and is WPMU compatible, if you want to rip the code out of it. Let me know if you run into trouble adapting the code.
