Update: new version available.
I got tired of always having to insert the same bunch of stuff for comment headers for functions, files, etc. so I put together an emacs minor mode to do all of the insertion and find-and-replace automatically. What started out as some simple keybindings has kind of grown into something (just a tiny little bit) more sophisticated.
template-mode.el is an emacs minor mode that allows you to bind keys to insert templates. As samples, I've got templates for function headers, function bodies, a file template and a couple of others. This was hacked together rather quickly... so documentation is a little sloppy. So feel free to drop me a line and I'll help you out (and, of course, write better documenation so I get fewer questions). You can get the package here. If you put together any useful template files, send them to me and I'll make them part of the package.
Please note that this is by no means mature, and I'm not any kind of emacs-lisp wizard. So let me know (email@example.com) if there's something I could be doing in a better way.
Download template-mode.el here: template-mode-1.0.tgz.