I just spotted this on the SharePoint team blog. Looks like a great resource for developers seeking guidance on best practice for WSS3.0 dev.
A snip from the post:
Have you wanted information on how to package web parts, event receivers, or list/feature/site definitions into solutions? How to deploy those solutions from a development environment to a test environment and then to production? How the deployment of application components and assets is different from content deployment? How to push a new version of a web part, feature, or application page out to a site that has the old version already in production?
This white paper covers it. So, go get it now!