While we register new domains here at WordPress.com, we're not able to accept incoming transfers of existing domain names. We therefore recommend that you keep the name registered at your current registrar (or, if you are not happy with your current registrar, transfer the domain name to another registrar). You can use the domain for your site here at WordPress.com by mapping the domain, as explained here: http://en.support.wordpress.com/domains/map-existing-domain/
Let me know if I can assist you with anything else!
