New development versions of Drizzle are released every two weeks. Releases are labelled YEAR-MONTH-REVISION This should not be confused with YEAR-MONTH-DAY. For example, version 2011.02.10 refers to February 2011 revision 10.
Development releases are available through Lanchpad at https://launchpad.net/drizzle/+download.
Subscribe to http://planetdrizzle.org/ or the Drizzle Discuss mailing list to be notified about all releases.