NOTE: I will update this post periodically.
Although my focus is on Dynamics CRM 2011 as a development platform, I get asked about Administration resources all the time. Basically, you need the fundamental admin skills required for the underlying technologies Dynamics CRM 2011 builds on: Windows Server, SQL Server (including Reporting Services), IIS, and understanding of how CRM Connects with Exchange and Active Director and then the CRM 2011 specifics. Here are a set of resources I typically point people to:
Microsoft Dynamics CRM 2011 Implementation Guide
Microsoft Dynamics CRM 2011 Administrator's Guide
Book Review: Microsoft Dynamics CRM 2011 Administration Bible
System Center Monitoring Pack for Microsoft Dynamics CRM 2011
Optimizing and Maintaining the Performance of a Microsoft Dynamics CRM 2011 Server Infrastructure
There’s also a Microsoft Learning online courses one might want to take:
Collection 80296: Installation and Deployment in Microsoft Dynamics CRM 2011
These resources should give you a sense for what it takes to be a CRM 2011 Admin.