You can do this by writing a CGI program that will accept arguments for the file name and the version to be viewed, check out the right one from RCS, and send it back to the client. If you want to get fancy, you can have a configuration page where a user chooses the version to be viewed. Then you set that version in a cookie so that you will know the version they want without adding it to the URL. By mapping a set of URLs using apache's Location directive, you can have anything under /rcs/* go to your CGI program which will then look at PATH_INFO to determine which file to show and the cookie to determine which version. Of course all of this can be done with mod_perl as well.