The Lotus position is held to be the ideal seated position in nearly every school of meditation. Depicted in the earliest texts of the spiritual traditions of Japan, China and India and even on the tombs walls of Ancient Egypt. It is a cross-legged sitting posture, in which the feet are placed on the opposing thighs. A properly performed posture offers a pathway to inner tranquility and self knowledge for those with the will to find it. This position is said to resemble a lotus flower, to encourage breathing proper to associated meditative practice, and to foster physical stability. The problem with this position is that, if incorrectly performed, it can cause damage to the knees.
This video teaches the principles of the easy, safe and comfortable adoption of the proper meditative position. You can find a complete systematic course leading to this meditation posture here.