ASP.NET 

• ASP Snippets

Umbraco:

• Umbraco Blog archive
• DynamicNode
• NodeFactory
• Create Your First MVC Project in Umbraco
• Moving from WebForms to MVC
• SiteCore
• Umbraco Blog  
• Umbraco Site
• An Umbraco Practical Example – A Case Study – Part 1
• Umbraco 7 and MVC Practical Examples
• Cultiv by Sebastiaan Janssen
• Examining Examine
• Getting started with Examine

Umbraco Razor:

• Umbraco Razor Feature Walkthrough
• Part 1
• Part 2
• Part 3
• Part 4
• Part 5
• Part 6
• Part 7
• Part 8

Sitecore:

• Learning Sitecore MVC - Part 1
• Learning Sitecore MVC - Part 2

Genaral:

• MVC
• SitePoint
• StackOverflow