WCF Best Practice #3: Contract first
In addition to the WCF Best Practices that are already around. WCF Best Practice #3: Contract first:
Not really a best practices but still an important thing to know if you’re new to WCF. WCF isn’t very good at developing contract first. By default you build services CLR based. WCF on runtime creates a WSDL and XSD’s of the CLR based servicecontract and datacontracts.
Important thing to know especially if you come form a world where contract first with XSD’s and WSDL’s is the approach like with BizTalk server.
If you do want to do contract first then check out WSCF.Blue this can help with this in WCF.
http://www.codeplex.com/WSCFblue/
http://msdn.microsoft.com/en-us/magazine/ee335699.aspx