Actually connecting the motor to a USB interface is one of more difficult ways.
To make the motor vibrate you need to apply a DC voltage.
It is hard for me to explain alternatives to someone with limited electronics experience.
The FEZs are very flexible and offer several ways of connections.
As mention before, an easy way is to connect a digital port on a FEZ to transistor and the transistor to the motor. The current required by the motor is too high to connect directly to the FEZ.
There is a single relay componet sold by GHI which could be used to apply the voltage to the motor. With this component you would not need to worry about the electronics, althought depending upon which FEZ you use you might have to do a little soldering.
The PC to FEZ communications could be done in several ways. The beginner ebook gives examples on several alternatives.
With a Cobra FEZ and the relay component, I could be controlling the motor from a PC within an hour.
I think most of the people here are more software than hardware, but we have a great group and we help each other work our way through the unknown.
I suggest you read the ebook. It will give you lots of ideas on how to achieve your goal. As you read the book, you can post questions on the forum for specific areas you have questions.