Information on careers in Classical Music is here:
http://www.learndirect-advice.co.uk/helpwithyourcareer/j obprofiles/profiles/profile1312/
The most common route to becoming a conductor is to study music at university (or at a music college with degree level qualifications) and select a module in conducting as one of the components of the course. Even then, only a very small number of those who study conducting will go on to become a conductor - it would normally still be necessary to spend several years performing in a concert orchestra after leaving college before applying for an initial post as a 'rehearsal conductor'.
Chris