Until I finish the definitive online video explanation of special relativity, you might want to check out The Mechanical Universe. Created by the Annenberg Foundation and now available on Annenberg's Learner, a conduit for distributing educational media, the serise includes some great visual explanations of relativity. Episodes 41 through 44 will probably give you what you are looking for.

You can launch the episodes by clicking on the VoD button next to a description, but you may need to turn off your popup blocker to launch them.

LINKS GOOD ON 2011-08-28

Special Relativity: Two Postulates (7m:12s)

The bizarre consequences of special relativity arise from two postulates, two things which once accepted lead to Einstein's space-time. In this video we will introduce these two postulates. In later episodes, we will use them to derive the consequences of special relativity.

LINKS GOOD ON 2011-08-28

Special Relativity: Nomenclature (3m:06s)

Last time (above) we covered the two postulates of special relativity, and next time we'll use geometry to derive some of its consequences, but first we need to learn some nomenclature. It's not exciting, but it will prove helpful in the long run.

LINKS GOOD ON 2011-08-28