We are looking at switching from using WCF for our service layer in applications to REST.
So far we are assuming that the way to do this is to use the WCF REST Start
I don't think it's going anywhere. It took 4 months to get from Preview 1 to Preview 2 and it's only been 3 months since then. Far from official, but this article names it as a highlight of Framework 4 - Beta 1. There was a PDC session on it as well. Too many organizations are using REST for their services to not have support in WCF.