A tweet sent by Cortana's program manager, Marcus Ash, reveals that inside of two weeks, a developer preview for Cortana will be available. Keep in mind that the only Windows Phone 8.1 users in the U.K. that will be able to see and use Cortana, will be those who registered as developers with Microsoft. For the rest of you, the personal assistant will be unavailable for now, unless a hack is devised, of course.
Right now, only those in the U.S. with Windows Phone 8.1 are able to use Cortana. In his conversations on Twitter, program manager Ash said that while developing Cortana, Microsoft learned a lot about scaling; that is certainly one of the issues that the company would have to face when rolling out a project as ambitious as a virtual personal manager, to a large number of countries world-wide.