I have finally managed to more or less polish my Multiple Site Manager for SharePoint application and publish it on Codeplex. You can get it from here:
Multiple Site Manager for SharePoint is a server tool which allows administrators to create, delete, and manage SharePoint 2007 sites, site collections, and My Sites either using a CSV file. Site columns with specific settings can also be created using XML.
Full details can be found on the Codeplex site. If you have any questions or requests for future releases, please let me know.