Speakeasy.NET:
Take the Speakeasy Speed Test and test your connection speed! By measuring the download and upload rate from the following locations you are able to accurately judge your current line throughput or internet connection speed.
SpeedTest.Net:
The flashed based broadband speed test provided by SpeedTest.Net allows you to test your connection with servers located around the world. Progress and results are displayed graphically, simple to use and understand.
2Wire.com:
This test is recommended for those users who have a 2Wire DSL/Cable Modem or Router. Broadband providers such as SBC, Att, InsightBB and others sometimes provide this type of equipment.
DSLReports.com:
This website not only has broadband speed tests but also many other tools and forums to help you with your internet problems. Their testing servers are located around the United States on dedicated connections to ensure accuracy.