Microsoft Dynamics CRM has become a buzzword now a days and all companies are betting big on it. Even Microsoft is projecting it as an xRM platform to get into all sort of industries and domains.
Many companies are building customized applications on Dynamics CRM to meet the business needs. Here is a link that would help you to learn Microsoft Dynamics CRM 4.0
It is mainly a Handbook for Users that helps them to know the usage of Dynamics CRM.