The title says it.
http://wiki.blender.org/index.php/Doc:2.4/Manual/Physics/Fluid
That link says I should keyframe all fluid objects to be enabled at the frame I want the simulation to start on, but it doesnt help.
In the fluid settings, there is a panel called time. By default, it is set to (start) 0.00 and (end) 4.00. This is the length of the animation in seconds. If you are running the simulation at 24 fps and want it to start 2 seconds in, change 0.00 to 2.00 (for example).