can i auto detect users conection spd?

Hello,
I would like to know if anyone out there has any info on any technology to auto detect a users connection speed? Instead of letting them choose and droping the cookie… but I would like to automatically route the user to a page tweaked for his connection speed, but I do not want it to be something that they are even aware of if I can help it…

Any info, thoughts, ideas, or other possible solutions would be GREATLY appreciated!
Thanks