Use Google's M-Lab To Test Your Internet Connection

Google has assembled a suite of free tools (developed by researchers, not by Google itself) that let you measure things like BitTorrent throttling, upload/download speeds, and last mile snafus. In exchange for “free,” the test data is being made public to enable further study of broadband connections. You might want to bookmark the site for future reference when you’re trying to figure out what’s going on with your ISP.

M-Lab [Google]