This Example has been updated using Solidworks 2008 (If the Images are two big for your screen size, you can Download them here)

1) Open the Hotrod.sldprt
2) Pick Parting line - See image1
3) Pick Draft Analysis before you leave the Parting line command- See Image 2 and click OK when it is finished
4) In this example you will need to shut off a surface, so pick Shut-off Surface
5) SW should pick edges automatically and in this example you should not need to pre-select the face - See Image 3
6) Make sure the "All contacts" is picked under "Reset All Patch Types"Click "OK" when finished- See Image 3
7) Pick "Parting Surface" - The Surface Loop should get placed in this command automatically. Change the surface extension to be longer than 5mm. I used 25mm. Click "OK" after you make your Property Manager look like mine. - See Image 4
8) Pick the face you see in Image 5. Do a "Normal To" the flat portion of the parting surface - See Image 5
9) Start a Sketch on this surface and make the box bigger than the part. But make sure it doesn't extend past the surface. Exit the sketch when finished - See Image 6
10) Now you can pick the Tooling split - Set your Core and Cavity to the desired thickness you want. As long as your Shut-off services are right then you should not get any errors when you click OK - See image 7.
11) Image 8 shows you after the Tooling split is completed, how to view the actual Core and Cavity. Using the Move/Copy body command allows you to pull each component apart to view each side. Hide and Show will allow you isolate each one.
12) To go one step further you, you can use the Split Body Command to split each part out into its own part file and also add each one to an assembly. But that will have to go into another FAQ.