Other than that your best option would be to go straight to your favourite Curry house and ask the resident Chef to do it for you. He'll still want paying but at least you'll be getting one on one instruction. You would be surprised but most Chef's would offer to help you, everybody likes to make a few quid on the side.
The other option would be to ask at the local food college for a curry course, most do them.
Finally there's doing as 976bar suggested and learning from here from scratch. There are some excellent recipes here, but like most things in life you only really learn from doing.
Most people here have spent years making curries, we all have learnt a lot from the time and effort they have put in.
Hope this has helped.