Best website to get info on childcare vouchers

Can anyone recommend a decent website to look at that explains what the childcare vouchers can be used for?

Currently we use them to pay for our two youngest to go to nursery a few hours a week & for our eldest two to attend an after school club one day a week but someone mentioned to me the other day that they use theirs to pay for their childrens swimming lessons. This would be fantastic for us as three of our children go to lessons. The children are completely cared for by the swimming instructor for an hour but although we can leave them they do recommend that we wait in the cafe until they have finished. I usually take along some sort of work to do or look through the aat forums while I am waiting for the children.