Saabotage

Last week I noted that I had lost about 1 quart of oil after driving 2K miles. I discovered this AM that there was oil on the garage floor on the passanger side. I use Mobil 1 and the oil was very clean. Any ideas on where I can start looking for the source of the leak. I am hoping it is simply but concerned that it is more major. I keep the engine compartment very clean and have not noticed any leaking before. The engine is running fine. Any ideas would be appreciated. Also if anyone knows the cheapest source for the Bently repair Manual that would be great also. I got a cheap CD but it is worthless