I have used both Codesmith (http://www.codesmithtools.com/) and MyGeneration (http://www.mygenerationsoftware.com/portal/default.aspx) over the last few years.  A bit of code from work is using CodeWorker (http://codeworker.free.fr/) and I’m not sure about that.  Then I read that Microsoft has it’s own code generation tool: T4!

http://spoiledtechie.com/post/What-Gives-Microsofts-Code-Generation-Tool.aspx