[Garth1388]

One method I found to be very effective, is to use the Design Accelerator feature of Inventor 10.

While in the assembly, there is a button with a picture of a blue bolt on the side panel. If you click on it, it will take you to a new window where it asks you to define nuts, bolts, washers etc.

I assume you will want to put bolts through the holes, so it should make it alot easier. But if you just want the holes, I'm pretty sure that you can only select to create holes without anything else. But if you can't, you could always create it with the bolt, and on the Browser Panel, delete the bolt. That will keep the holes there.