The session 'Turn Left or Right? How to Best Design Your Web Services Interface' at TechEd was very interesting and pointed issues like versioning, contracts, interfaces, etc.

Christian Weyer from ThinkTecture is currently building a tool called WSContractFirst (WSCF) that can generate code from a contract. Dealing with the "Melted Cheese Effect" is an article on MSDN about this subject and more parts will be published.