Multi threaded webserver vs single threaded
Step 1.  Use Apache.  It may seem like overkill but it's cheap multi-threading with no programming on your part.  Apache can be configured to fork off several servers.  No programming on your part.
This may be sufficient to make your application run concurrently.
Step 2.  Rewrite your application to use the wsgi framework and embed it in the wsgiref server.  This won't change much, but it's the way you should always write small web applications.  
Step 3. Use mod_wsgi in Apache.  It allows you to have one or more background daemon versions of your application.  With no additional programming you get a heap of concurrency available to you.
Important lesson learned.  Always use WSGI.
We have a simple webserver for internal use that has only one duty: listen for requests, read them, and push the data in a database. The db and webserver are both located on the same machine. The db is a mysql-db and the server is a python webserver (BaseHTTPServer.HTTPServer) which runs single threaded. 
The problem is that two requests can't be handled at the same time. The question is, would it help to make the webserver multi-threaded (using django, cheryypy,..)? Intuitively, the webserver is only performing CPU consuming tasks so changing it to multi-threaded shouldn't help. Is this correct?