As many reported (including me), ADO.NET team decided to postpone the EDM designer after Orcas/.NET 3.5 RTM. With this move they basically frozen the use of EF in real applications (wizard is very limited, typing all that XML is not really an option) until EDM sees the light of the day.
Now it is getting even worse. They decided to postpone entire EF for the time being mentioning H1/2008 as a tentative release date. It is amazing to see a huge company, full of money, full of very talented people, like [MS] that can't create an ORM in years (remember ObjectSpaces?). Whether this is politics or misjudgment or something other is hard to know for sure, however, they certainly aren't lacking the resources, are they.
So, what do you do in the meantime? Either start playing with LINQ to SQL or go with LLBLGenPro a proven, reliable, powerful, excellent ORM solution that is ready to use right now.