>What approaches do you suggest for doing team development where all developers can create classes in a common class library. We have tried to use Visual SourceSafe to manage the conflicts between developers but to no avail. Visual SourceSafe only lets one person check out the class library at a time.

Keep the number of classes stored in each library small. And logicially store the classes to minimize conflict. Don't store customized classes with "base classes" in the same library. Just a couple of ideas.