Several websites can get you started in terms of how to observe and when is the next event :
The site of European asteroid occultation network (EAON) lodged by astrosurf
The very useful site of Eric Frappa: Euraster.net.
The site of reference for the follow-up of lunar English occultations is that of Iota (The International Occultation Timing Association). Many things also to be drawn on the site Boreal Zenith, and not only on occultations and the transits of planets.
The Site of Jean Montanne also contains interesting information on star occultations by asteroids.
One can download free on the site of the DOA (Dutch Occultation association) the software Lunar Occultation Workbench, which makes it possible to calculate occultations of stars
The Jan Mánek asteroid occultation site related to the Czech Astronomical Society.