http://www.w3schools.com/sql/sql_view.asp - The basics of understanding how to create views is available at w3 schools, and this will get you through most of view creation.
http://msdn.microsoft.com/en-us/library/dd171921%28v=sql.100%29.aspx - Materialized or indexed views are a crucial component to being able to improve performance.
http://msdn.microsoft.com/en-us/library/ms187956.aspx - Documentation for SQL Server CREATE VIEW
Views Example using Registration System - Demonstrates how to create a view from multiple joined tables.