If you and your colleagues use Microsoft Dynamics CRM to collaborate on the records you keep, you should watch Microsoft's newly published videos:
Sharing and Assigning Records (CRM users):
Learn how to share records and assign records to another person or to a team so you can collaborate across your organization and increase awareness of information. You can also read step-by-step instructions for assigning and sharing records in Share or Assign Records.
Sharing and Assigning Records (CRM Online users), which explains how to enable teams to work together on individual records in the system.