Does anyone know where to download the Windows Server Update Services (WSUS) 3.0 without any service packs?
Sure. Go to the Windows Update Catalogue and do a search for "WSUS". It will then display all the previous versions of WSUS. Find the version you want (3.0, no SP) and click "Add".
Once you have added it to your basket, click "View Basket" (at the top, under the search box", and then click Download.
And voila, WSUS 3.0, sans service pack.