pairodoxfarm on "Transfer domain to wordpress ... ordering of events."

Hi. I'm sure you've had this question before ... so forgive me. I currently have a domain hosted and administered by a local ISP. The domain is http://www.pairodoxfarm.com. I'd like this domain to switch over to my blog (www.pairodox.wordpress.com). I know that my local ISP administers my domain ... if I call them and cut them off ... how do I seemlessly transfer the domain to you without losing it? And, who pays the folks who maintain domains? I know that it costs to keep a domain. If I sign on with you - do you pay the guys who hold the domain name? I'm confused. OK. So, I sign up with you ... follow all the appropriate prompts ... and only then do I cut off my local ISP? And then I pay you each year ... to pay the folks who maintain domain registrations? Right? Please let me know the ordering of the steps I need to take to transfer http://www.pairodoxfarm.com over to you and substitute that for http://www.pairodox.wordpress.com. Thanks.
Blog url: http://pairodox.wordpress.com/