The first place to start is by asking yourself this question:
Can you cope with 12 hour days, plenty of paper work and government red tape, your home constantly being messy and never quite as spick and span as you'd like, things getting broken/damaged pretty regularly like walls/doors/carpets etc. Would your current children mind their toys and home not really being their own for the next few years....
Do you mind that your income would never be stable and that parents will mess you around a lot, they might not pay on time, they might not pay at all, they might ask you to do all sorts of things that you might find absurd.
Do you mind the sticky fingers, constant noise, runny noses, tears, tantrums & wet bums?
If you reckon you can cope with that (and more!) then you probably need to look at ofsed site but my warning to you would be childminding is not a profession where you will make big bucks. It might seem that a nursery is making big bucks but I don't know any childminders that are well off considering the hours they put in. Also you need to think about the ages of your own children and the number of children you would be allowed to care for.
I think childminders do a really great job on the whole given what they have to put up with so if you do love children and think you would be a brilliant influence in a child life then go for it; but don't do it if you are thinking it's easy money.
Good luck!