Excellent introductory tutorial on v3 web parts development, Charles!  Even though, I am watching this over a year after the fact, I have a couple of questions: are the *.webpart files stored in the SharePoint databases after SharePoint creates them?  Second, do I have to modify the web.config file and install the *.dll on ALL web servers if I have a multi-server/cluster farm deployment OR does SharePoint somehow replicate this for me?

Thanks in advance, Charles.
Shola Salako.