There are a number of ways of becoming the owner or part owner of a racehorse. Whilst outright ownership is probably the most thrilling way to attend the races, the most practical for most people is to join a syndicate or club. Many of the stables in Lambourn have syndication facilities or will be able to put you in touch with someone who can assist you.
Independent advice is also available from the British Horseracing Authority who have an excellent website explaining the different types of ownership and a list of the clubs and partnerships operating at the moment.
Please note: Ownership in racehorses is highly speculative and can prove to be a total loss financially.