“Will there be a public beta for Entourage?”
The answer is highly unlikely. There has never been a public beta for the Mac Office applications. Software Activation is not available for Mac Office. Without software activation, the software pirates could produce bootleg copies of the software from the beta version.
Microsoft has offered a “Test Drive” version for both Office X and Office 2004. I’m confident that there will be a “Test Drive” for Office 2008. You’ll just have to wait for the Office 2008 Test drive to be released to give it a try.
As the adage says, “past performance is not a reliable indication of future performance” but don’t get your hopes up.