Hi djcali,
Here's a quick step by step for one method (there are several other ways to do this as well).
First create a sketch down the center of the work piece, using an existing origin plane (or by creating your own work plane). Create a line at the correct and angle coming off the center of the work piece, and use a dimension to set the line length. I've dimensioned the line length at 2" but, as long as it goes out past the intersection of the face of the work piece by a bit, the length doesn't really matter.
Next create a work plane on the end of the end of the line by selecting the end point and then the line.
Then create a sketch on this work plane and use the Project Geometry tool to project the line end point into the sketch. You can then either toggle the projected point to be a center point cross, or place a center point cross onto the projected point.
And then finally use the Hole tool to create a hole that goes through all, using the sketch point as the placement.
Attached is an example file as well.
I hope this helps.
Best of luck to you in all of your Inventor pursuits,
Curtis
http://inventortrenches.blogspot.com