EDIT: The url can be found here; https://www.siriusxm.com/player/mybeta/#view=login
I have on good authority that "MyControl" is being run in a very small limited public beta right now and it will likely be re-branded "MySXM."
I wish I knew more but, I don't have access yet -- I'm working on it. In the meantime, I would encourage anyone with web player access to login and see if they are part of the beta. If you are, please note the URL in your browser and report back here.