From Daniel Beardsmore:
HTTP Werkzeug is an HTTP send and receive tool, to let you see the HTTP sent by a browser, and show you the HTTP returned by servers. It allows you to generate HTTP requests to servers, and view the results. It takes care of some of the techicalities for you: Host, Referer and User-Agent request header lines can all be generated for you, and it is supplied with a customisable selection of user-agent lines to choose from. This makes the task of working with a server a lot easier than using a Telnet client. You can also have a browser send HTTP Werkzeug a request, and it will show you the HTTP that the browser produced. This allows you to test a server by mimicing the types of requests that different browsers make, the User-Agent line in particular.