For stand alone games, the basic game loop is (source: wikipedia)
while( user doesn\'t exit )
check for user input
run AI
move enemies
resolve collisions
It would be something like
Client:
while( user does not exit )
check for user input
send commands to the server
receive updates about the game from the server
draw graphics
play sounds
end
Server:
while( true )
check for client commands
run AI
move all entities
resolve collisions
send updates about the game to the clients
end