How to make truffle oil?
Basically, it is that easy.  But it is a costly endeaver.  I have know chefs to make it with a pure olive oil or grape seed oil.  Some heat it to 220 degrees or so but I have meet some that don't.  The ones that didn't made sure to pull the oxygen from the bottle with one of those wine vacuum savers.

I have been told self made truffle oil will lose it truffle flavor due to most the flavor actually coming from an odorant.  I have not personally made any so I can't speak from experience on how long it will hold.

All the above being said. If I had the money to buy some truffle, I am not sure the best use for them would be to make truffle oil.