Did you know that http://maps.live.com/ now provides up-to-date traffic information shown using different colors (green, yellow, and red) to indicate traffic conditions along your route?  Of course, you can remove it by clicking ‘Hide traffic conditions’ link…

 

It appears that, at this point, the information is available only in some major metropolitan areas, but it’s a great start, in my opinion.

 

You can also download a Windows Vista gadget for your desktop that provides traffic information for a selected geography auto-refreshed every 2 minutes.  Check it out at http://gallery.live.com/liveItemDetail.aspx?li=d5ad423c-05bd-4de4-8803-b05ecc339397&l=1.