I found the following articles from MSDN for MOSS 2007. I hope it would helpful to you to explore MOSS 2007.
1. Operations for Office SharePoint Server 2007
2. Deployment for Office SharePoint Server 2007
3. Planning and architecture for Office SharePoint Server 2007
4. Security and protection for Office SharePoint Server 2007
5. Technical Reference for Office SharePoint Server 2007
6. Windows SharePoint Services 3.0 technology
7. Office SharePoint Server 2007 for Search