I haven't got round to making a tool to do it, but it's simple to do when access to SQL Enterprise Manager/Management Studio.
First of all, backup the content of the document you are going to change. This is important, as changing the content type wipes the content. I don't know why, the developers will know the reason for that. But the bodyText and the properties dissapear. Changing the contentType is straight forward, simply run
in SQL Server Management studio. You can get a list of contentTypes from the contentType table. nodeId holds the ID (rather than the pk column).
Once you have done this, publish your document. It will probably show a null reference exception when you click on the node in the editor. This will go once it has been published.
Truncate your umbracoLog table regularlyThe table contains all exceptions and warnings plus a host of other information from the Umbraco system. Most of this you don't need and can clog up the database. The table can grow very large quickly, particularly if you're creating the website for the first time and testing. This image shows an example
Before this the site was 500,000 records strong before I noticed. The backups become large too. So simply run truncate on it:
There's not point saving the deletes to the transcation log with DELETE FROM, as the data is never used by Umbraco except for your information.
Make sure tracing and debug is turned off Find the following lines in your web.config file and make sure the attributes are set to false, it makes a noticeable difference:
GZip your HTML output I've written a small HttpModule based on some code by Bart De Smet that's very simple to install. It GZIP's your HTML output, reducing the bandwidth your site uses and page load time. It's aimed at people using shared hosting or pre-IIS 5 servers.
Download
This tool came from having troubles backing up an Umbraco database on gate.com - who didn't allow user backups of SQL databases or remote SSIS packages. The host has now been switched but for users of similar hosts like godaddy.com the tool is useful. Find it at:
http://www.codeplex.com/UmbracoExportTool
Version 2 documentation PDF http://umbraco.org/media/4d051ed3-63c2-42d6-a6c1-e93a14fc24a8-UmbracoDoc.pdf
Old documentation (some isn't on the new site yet) http://old.umbraco.org/frontpage/documentation.aspx
Wikibooks http://en.wikibooks.org/wiki/Umbraco
Official utilities:package http://www.umbraco.org/frontpage/download/extensions/umbracoutilities.aspx
Large amounts of packages http://rtk-cv.dk/1050.aspx
Lots of information and links http://ismail.umbraco.net/ is a great place to browse for information, the links section is also very handy.