As is mentioned in this new post by Paul Jones the Solar framework project has reached its "beta" status on December 18th, 2009 and has just hit another milestone - beta2.

Along with the release comes updates to the manual including a new blog tutorial that walks you through the creation of a simple blog that shows you how create the basic application structure, add actions/views for the CRUD (Create, Read, Update, Delete) of articles and work with local strings.

If you're looking for what changed in the two betas, check out the release notes for beta1 and beta2 (download link for the beta2 release).