Microsoft has released a white paper regarding solution lifecycle management.
This document provides interesting information about methodologies and processes to handle solution development, deployment and test during enterprise scenarios.
Moreover, this document describes how to integrate CRM solution package into Visual Studio (and also into TFS source control) with Solution Packager.
This step is the key to facilitate versionning and branches management.
If you want more details about ALM & CRM, you can take a look to our TechDays presentation (in French, sorry) :
ALM for Microsoft Dynamics CRM 2011 : CRM Solution Lifecycle Management is available on Microsoft Download.