The speedtest.net site has a free mini edition
(http://www.speedtest.net/mini.php) you can download and extract to
some http available path (asp, php, jsp all supported). It's a flash
applet, easy to wrap into your own page. Transfers one of ten large
JPG files of random noise (largest is 31MB). IIRC, it somehow does a
pretest to select a file that should take > 10 seconds.
If you're connected at >100Mbit to the hosting server then the results
are rather bogus (not enough time in flight to get any meaningful
averages).
Demos (found via google): https://test.kems.net/
http://speedtest.qualitynet.net/ http://speedtest.fsr.com/
Pros: not a java applet
Cons: adobe flash applet