Here are the four links which I found helpful and easy to understand:
The diagrammatic view of page life cycle ASP.NET Page Life Cycle Diagram
Shortcut Overview Page Life Cycle in ASP.NET
The ASP.NET Page Life Cycle (by Solomon Shaffer)
Microsoft development network MSDN
What is the best way to explain asp.net page life cycle. There is so much information that i am unable to find the relevant ones.