There is a [**Code Preview Handler**][1], but it supports only the extensions .cs, .vb, .js and .sql . The source code is available and it doesn't look too complex to create a Preview Handler (well, sort of, I wouldn't know how to do one).   

I tried adding other extensions to the Code Preview Handler with the tool [**Preview Handler Editor**][2] but it doesn't work, the preview pane is blank (at least for the .pl files I tried).

![alt text][3]


  [1]: http://timheuer.com/blog/archive/2006/12/13/13945.aspx
  [2]: http://blogs.msdn.com/toub/archive/2006/12/14/preview-handler-association-editor.aspx
  [3]: http://img260.imageshack.us/img260/1686/capturelj.png