There are already plenty of load testing tools out there that are open source, multi-threaded, fast, powerful and easy to use. My favorite is httperf.

http://freshmeat.net/projects/httperf

And if you want to make it one step easier to use to record your actions and use them for the load test check out my HTTP::Recorder::Httperf module on CPAN that uses HTTP::Recorder to record you browsing as an httperf session log.

http://search.cpan.org/~wonko/HTTP-Recorder-Httperf-0.02/lib/HTTP/Recorder/Httperf.pm