ntl guy (mate of mine) suggested this site to test your download and upload speed. Sorry if it's been posted before.
What does this do? it tests your line speed, both upload and download. The test servers are located in quality data centers for maximum accuracy.
This test is a transfer of nearly uncompressable data (actually, mp3 files). The result shown is your data transfer speed. This should be close, but less, than your rated (purchased) line speed. If you can get close to 90% of your rated line speed, everything is perfect!
http://www.dslreports.com/stest?loc=2