I wouldn't use the arduino as the web server, I'd use it to pass details to a web site somewhere else.
If you have access to web server running PHP [edit: or ASP] (they're free, you could set one up on your home PC), you can create a web page that gets data from the URL. If you're passing weather data you might have:
index.php?temp=60 where the value comes from your temp sensor. The php web page can grab that data (using the GET method).
You web server will far more suited to dealing with the data than your arduino, so you'll be able to feed that into a database and output it as a graph.
As far as I'm aware you need to find the web server by IP address, so might be a bit tricky if you opt to use shared hosting, but if you're using a local host it'll be fine, and you'll be able to forward the port properly.