Yes, there are chemical means of attraction between the sperm and the egg but the interesting part is being left out in other responses. The actual chemical mechanism is polarity. The sperm are attracted to the egg by opposite charges and when one sperm arrives, the most interesting part of all takes place. Since two sperm getting inside an egg is not compatible with life (polyspermy), the egg has to be selective and only allow one sperm inside. So, when that first sperm comes into contact with the egg, the polarity of the egg immediately switches charge, thus putting out a force-field that repels other sperm away from it. This is known as the fast-block to polyspermy.