Tim : you need to look at this site where you will find all you need to know about the new pension regime. If you need to know more I suggest looking at the SIPP board on www.fool.co.uk - it is easy to get answers to questions there.
Essentially from April next year you will be able to take an Alternatively Secured Income (i.e. drawdown) for ever, instead of taking out an annuity. Also what is left in your pot after you eventually go can be passed on to your heirs by moving it into their pension pots.