RoundRobin DNS?

[Vasiliy Boulytchev]

Ladies and Gents,
    This is a first time I get a client big enough that needs this solution.  Imagine a scenario, that you have a web server that can't go down.  So you put it up at 2 different locations, say one in LA, other in NYC.  So if say the ISP in LA goes down, NYC should theoretically start getting requests for webhits.  That's what this client wants.  So how is this done, I'm not sure this is done with DNS at all, although its a possibility.  When I querry yahoo.com with nslookup, I get a few different ips. HOW IS THIS DONE?   Can someone please point me in the right direction?



THANKS A BUNCH


Regards,
Vasiliy Boulytchev
Colorado Information Technologies Inc.