DotNetNukes .Net Open Source Framework for web applications

I just installed

DotNetNuke a free, Open Source Framework ideal for creating Enterprise Web Applications.

It has great functionalities. From creating a web site, a blog, etc.

Creating users for editing page contents. Giving rights to users to edit pages or modules in pages.

One thing I found difficult is changing the skins. The one provided with DotNetNuke is not so helpful.