of consolidating three disparate Active Directory Domains into one new Windows Server 2008 Domain

Hi

I need some help if possible to give an overview of consolidating three disparate Active Directory Domains into one new Windows Server 2008 Domain.

Covering the following areas

Planning
Testing
Implementation

Pay specific attention to the areas you would need to take into consideration and how you might mitigate any potential issues you may encounter (if any).

Thanks
Andy