> I am playing with Webrick and I tried to change a little the example given 
> with the packet but when I fill a html form and send it the fields values 
> are empty (using GET method, Webrick doesn't accept POST method). How to 

Webrick accepts POST method. Just define a method do_POST(req, res).

[...]

>    name = req['fname']

use req.query['fname'].

HTTPRequest#[] returns values from the request header. For example:

	req['Connection'] # => keep-alive

The values you are searching are in the array returned by HTTPRequest#query.