Nick, I think blade might be talking about making a template.
Blade, I think we'd need a little more information from you. What version of VMWare are you using? Are you using the virtual infrastructure client? Are you on a SAN?
Templates are a built in feature and are pretty easy to do. I am using ESX 3.5 so thats the version I can explain. You take a base build of virtual machine, get exactly how you want to use it (memory, disk size and quantity, CPUs, run all your updates, put it on your domain, install and update virus scan etc) from there you power off the VM (or in later versions you can leave it on) and in VIC right click on the machine and select Clone to Template. Then when its done, you can power on the machine, you have a template done and you're ready to go.
When you are ready to deploy from the template, in VIC you click View then Inventory, then select Virtual Machines and Templates. In your tree select the template, right click on it and say deploy from template.
A few "gotchas" when creating your initial machine make sure you use DHCP for an IP address and name the machine in Windows something like "Win2003Temp" because if you name it the actual machine you are using, lets say you name all your machines 001pc, 002pc etc, if you name your machine that then make a template of it, every time you deploy it out you'll get a duplicate name error on your network and cause problems for both machines until it is fixed.
Once you deploy the machine the only thing you'd have to do is rename it and set it to a static IP if you need to then run your updates to get it caught up.
Speaking of updates, another thing I am doing is about every 3 to 6 months is to deploy out the machine, do all the updates and then re-clone it. Makes for deploying faster if you don't have so many updates to do.
I think this what you're asking for, correct me if I am wrong.
Cheers
Rob
The answer is always "PEBKAC!