hi, does anyone know a good book or some lecture notes on the theory of frechet manifolds ?

There is the book by Kriegl and Michor called "Convenient setting of global analysis" published by the AMS. It goes much beyond Fréchet and really gives a big panorama. However, it is not easy reading and requires really some work. But I guess that is due to the subject... 


You could try
And there's a paper by Milnor on infinite dimensional Lie groups which could be useful. 

