British Museum - Natural History best collection in the UK and a great website too. They also publish a very good book at a reasonable price

NASA's Jet Propulsion Lab Near Earth Object Program including a great multimedia presentation and also their Mars meteorite information

European Space Agency's Hubble Space Telescope site asteroid images

Buy space rocks at reasonable prices from a UK teacher at www.spacerocksuk.com. From pocket money specimens for youngster to special kits for schools designed to support the Space@School website activities.