The enTourage forums are now gone, as is the enTourage store. www.entourageedge.com
posts a simple notice that ebooks are no longer available. The Registration server is still up though, and there's instructions for using Google Books for ebooks and the Amazon App Store for getting apps (happy news for Americans only...).
However, the Knowledge Base tab is there, providing access to support options, so technical support and warranty support apparently are still up.
Indications are that very limited services will continue for the foreseeable future, which likely means at least 4-8 months.