Where is the documentation?

[Mikkaels]

Is there any user documentation for CMS made simple?

[spoonicus]

There's nothing that's all in one place that I've been able to find. I'd settle for a comprehensive list of tags and their options, but all things being equal, I'd rather have the working product first.

Look at the Wiki, read the forums and hit up the IRC channel. Looking at the source code for the modules is helpful too.

[Akrabat]

In addition to spoonicus' points, most modules that I've seen have a help section that's accessible from within the admin interface (Extensions->Modules menu item). In general, you can find the available tags for that module listed there.