Yes, the beta is available, but the availability of purchase is unknown at this point.
I'll try to clarify.
If you have a current subscription on your LiveID that will expire in January 2008, and you remove 1.6 in order to try the beta, your subscription clock continues to count down while you are using the 2.0 beta. Your expiration for your subscription is still January of 2008. If the beta ends in November, you will need to uninstall the beta, reinstall from http://onecare.live.com and activate with your subscription LiveID. If you do this before 2.0 is placed up at the above URL for download, you will be installing 1.x, but it will automatically update to 2.0. It will not affect the duration of your subscription.
If you install the beta 2.0 and activate with a beta LiveID that you had used with a beta product key to activate, you will be inheriting the expiration of that beta subscription as you are no longer in trial mode. The trial of the 2.0 beta will not expire until the beta has ended. At that point, you will be able to reinstall 1.x or purchase a new susbcription after installing the released version of 2.0 and activating.
-steve
