This is probably a dumb question:o but how does one do load balancing among multiple database servers? How are the servers constantly kept in sync? With the data that must constantly be exchanged to keep them in sync, is it even worth having load balancing? It seems to me that it would take double the amount of time to do a database write, but half the amount of time to do a database read.

I believe what you are looking for is SQL Replication, it does take a little bit longer to write, but if you get to the point where one server can not handle the ammount of read/writes then you *need* to have additional servers to space out the reads etc.