How do I wire multiple switches for my bathroom lights and fan?
If I understand your layout, you could wire it like this:



Chaining to all four lights like this requires the use of 12/3 cable for the first two sections, but if you want to follow Tester101's suggestion and add the extra conductor to the fan circuit for possible future use, you're going to buy some 12/3 anyway.

EDIT: Carl Witthoft is correct, the bathroom should be protected by a GFCI. I have altered my diagram to show a GFCI outlet with downstream protection.