I just saw this post on Rob Caron's blog. Registration for the 71-510 Beta Exam is now open. The exam can be taken between February 20th and March 5th. There are a limited number of slots available on a first-come, first-served basis so sign up quickly! I signed up this evening without any problems.
Use the promotion code TSVS510 when registering to cover the cost of the exam.
There is a preparation guide available here. The list of topics is quite length so I'll definitely be spending some time brushing up on a few areas.
See Rob's post for more details.