Rather than repeat everything – Christophe has a great posting with all the links! http://blogs.msdn.com/chrisfie/archive/2009/04/28/announcing-service-pack-2-sp2-for-microsoft-project-2007-and-microsoft-project-server-2007.aspx.
I will just remind you of the Webcasts tomorrow (29th) and Thursday (30th) - I encourage everyone to attend the Project 2007 Service Pack 2 Overview webcast scheduled for April 29 at 8 am Pacific Time, and April 30 at 5 pm Pacific Time (webcast details are posted on EPMConnect). Adrian Jenkins and Christophe Fiessinger will cover the following topics during the webcast: SP2 Overview, April Cumulative Update Overview, Deployment Best Practices, Next Steps, Questions and Answers.
Another part of the SP2 announcement to highlight is around requirements for the next release of SharePoint and Project Server: Windows Server 2008 and 64 bit. We will be publishing guidance on how to upgrade your existing Project Server 2007 farm to Windows Server 2008 64 bit in the coming weeks on TechNet. Expect full system requirements for Project Server 2010 at a latter date.