.....In some situations "little" sounds more juvenile than "small", so I �d avoid "little" in extremely formal situations, but otherwise there �s no difference that I can detect.
Small is used most of the time when forming comparatives and superlatives. [...]this means is that "little" can be used as a quantifier, denoting the amount of something, whereas "small" denotes size. There are some odd differences that you will run across, .... For instance, little carries an emotional factor that small usually does not: a strange little creature, a little troublemaker. Also, little tends to be more a premodifier: You made some small/little mistakes vs your mistakes were small / (?) little.  �Little � is often used in a derogatory and abstract sense as in: of little importance/significance. Little help was offered to the poor. (not much) She showed little interest in his remarks. Small often relates to physical size with objects/people - a small person/ a small present/gift.....

                                 From one of the chats in the net