Broadband speed testers

DSL ZoneUK speedtest - You need to be logged in for this, this records every test.

thinkbroadband speedtest - Requires Java, also tests upload speed.

Broadband speed testers using files

ADSL24 speedtest - Hosted close to Entanet's data centre.

Unrealadmin file test - Download for the UT2004 dedicated server.

ISP review sites

DSL ZoneUK - The best one for reviews.

ISPreview - I don't use this one too often but it's been around for ages.

thinkbroadband - I mainly use the forums but this site has a compare option aswell.