WSS 3 is a great application but I have to say that the upgrade from the WSS3 technical refresh version to the RTM was very painful.
2 important web sites where running on the WSS TR before the upgrade and after it... were not working anymore. It took me many hours to solve the problem. So after all that I think I'm able to give some recommendations for any kind of upgrade to WSS.
- If you are running WSS3 TR make a backup of the complete server farm using the SharePoint 3 Central Addministration site. Go to the Operations section and find the "perform backup" option.
- Check that the backup was finsihed without errors.
- Make a copy of all the content databases of your WSS sites and include also the log files related to them. Locate the copies in a different folder.
- Using the SharePoint Designer (Latest version) make a backup of each one of your sites.
- Install the WSS 3 RTM. If you are lucky all will go fine... If you have the same problem than me... you will find that you have any of your sites listed within the Web Applications list. If that's the case you will need to create a web application per each web site you had before. Then you will need to remove the content database of each one, restart the IIS and use the STSADMIN.EXE to add the old content databases. You must use the STSADMIN because it converts the databases to what WSS3 needs.
If all fails... you have the back ups and you can contact me using this post. Good luck!