Kate's idea is a great one .. I'm not a fan of yell.com for the pushy tele sales techniques they use ~ but give the YellowPages a ring to make sure you have a free listing in the directory, under Childminders that will be delivered to your area ..
This is the number for the Yellowpages
0808 100 8182 ..
You could sign up with Yell.com here
FREE LISTING ~ Just be
veeeerrry careful of 'not' signing up on the paid for advertising .. Im not so sure it will benefit you as much as the 'paper to home' editions would.