Sorry to hear you're having problems transferring domain name away from Yahoo - they can make it a real pain.

You need firstly 'unlock' the domain at Yahoo. That is easily done via the online interface.

You need to make a transfer request FROM the registrar you're hoping to move the domain name to. The one I recommend is this one but there are, of course, hundreds of others.

You need to confirm the transfer by clicking on the links in the email(s) you will receive. It will take a few days.

If you have any problems then you can ring Melbourne IT on the numbers here. They handle Yahoo domain registration.