What qualifications do you have currently? And what flavour accountant do you want to be?
The three biggest accountancy bodies in the UK are CIMA (management accountancy - if you intend to work in industry), ACCA (more focus on tax / audit stuff than CIMA, but still acceptable in industry) and ACA (more relevant if your going to work in practice).
I'm a management accountant. I did a non-accountancy degree, and then studied for my CIMA exams for three years while working in industry.
If you have decent A levels or a degree, I would recommend getting a job and then joining which ever institute your employer recommends and will support you (financially and with time) to study with. To be honest, I don't use much of the stuff I learned on a day-to-day basis - it's more about an awareness of the issues.
If you don't have A levels, I'd recommend that you start with AAT (accounting technician) - again while working - and then move on to the higher level qualification.
One thing about studying - I'd recommend choosing one of the big providers, like Kaplan, rather than your local college. They'll be more expensive, but hopefully your employer will be paying - and in general they have much better tutors and much better pass rates.
Probably waffled enough now - but shout if you want to know more.