There is some buzz around about SQL Server 2008 being out in August e.g. on SQL Server Central, however that’s more than I know. I do know that it is listed in the August price list and that pricing is no different form SQL Server 2005, which is more than I can say for some other database products or the price of fuel.
As far as release dates I know it will be out by the end of Q3 this year but that could be 11:59 pacific time on 30 September, although I am hoping it will be out before SQL Bits so I can demo against the release rather than RC0.
However I am always curious about who really cares about precise dates apart from journalists who will flame Microsoft if 'it’s late, but what about the DBA who wants to use it? IMO all I think you/they need is a plan date and to know what’s in it that justifies an upgrade or migration. For example McLaren Electronic Systems are on the SQL Server TAP Program because they want to use Filestream, ITV.com are very interested in resource governor, and there is a lot of early adoption activity around spatial data.
Bottom line - It will be out sometime in Q3 when it’s ready