This article is a part of a series describing the installation of Microsoft Office SharePoint Server 2007 (MOSS) on a Windows Server 2008 with the newly released SQL Server 2008. Now we are going to install an Active Directory which may not be needed in your case. If your company has it's own developer Active Directory you can reuse that.
Update: 60 min - Install SharePoint with PowerShell easy and fast
The advantage of using your own Active Directory is that you are independent. You can manage everything by your own for example creating new domain accounts or doing password resets. It's comfortable and your environment is closed which means you don't need resources outside your environment and if you do something wrong you won't be affecting someone else.
Using domain accounts requires more work, right? No it doesn't... it actually saves you time and work. Your customer will use domain accounts to install SharePoint 2007 and that's why you should too. If something soesn't work for your customer it might bebecause of different accounts. So how do you check that? Or how can you be sure that it's not related to the accounts and you need to look for another reason? It really simplifies work...
If you don't have special requirements regarding the Active Directory you can consider using an Active Directory 2003 instead of a Windows Server 2008 AD. There are different functionalities but if you are not limited to one your virtual images created with an Active Directory 2003 are smaller in size. The copy process is shorter and the amount of memory used is lower so you can use your resources in a better way.
Please have a look at:
Right now I'm working on the SQL Server 2008 image.
Open the "Run" dialog box and type "dcpromo".

Click next without checking "Use advanced mode installation".
Click next and after that check "Create a new domain in a new forest".

Type a new full qualified domain name like "aglaser.net".
In my environment I set the forest functional level to "Windows Server 2008".

Make sure "DNS server" is checked.
After clicking next you may get a warning that one of your network adapters has a dynamically assigned IP address. Click "Yes" if you are sure you have one network adapter with a static IP address.

Click "Yes" because you don't have to care about a DNS server in a parent zone since this is a testing environment.
Click next again.

Type in a "Directory Services Restore Mode Administrator Password".
Click next to start the installation wizard.

After installing the AD and the DNS server you have to restart your computer.
If you take a look at the roles you will see that "Active Directory Domain Services" and "DNS Server" are checked.
