If you want to read more about it you can check out a review at Digital Photography Review.
The only lens I have so far is the Lumix 20mm f1.7. This is a very fast lens that is the "perfect normal" length for the camera's sensor. As I understand it that means there will be no distortion in the image... because the size of the sensor is equal to the focal length of the lens and gives photos the appearance of being a normal view, instead of being wider than normal (in wide angle) or less than normal (in telephoto).
You can find more about this lens by reading it's review at Digital Photography Review.