For those of you who want to use the stock ACC switch but don't want to bother with connecting a relay for the LED to illuminate, connect the PCV using this procedure.
(1) The end connector for the ACC switch is under the seat fitted with a rubber cap, and if you connect the PCV there you will eliminate the need to run wires under the tank. OTOH you must pull the P&A fuse first, as you don't want 12V flowing through the PCV at any time. The P&A only powers the ACC switch on the '07 and '09 (the only manuals I have), but check your wiring diagrams for your bike, as on other models it may power something else that won't work once you pull the fuse.
(2) You can cut the O and O/R wires at the connector under the seat, then splice those into the wires going to the PCV. Or, tap into them without cutting, but either way be sure to insulate well with tape or heat-shrink. To avoid violating your stock wiring you can buy an adapter from HD. Cut one of the end connectors off the adapter and splice PCV wires to the O and O/R wires. The other connector won't be used, so you can cut that one off too if you want to get it out of the way.
(3) With the PCV connected to the computer via USB cable, go to PC Tools > Configure > Map Switch
and check the box for "Enable Map Switch." Once this is enabled when you retrieve or send a map you will have the option of sending it to Map 1 or Map 2. You can now load the appropriate maps and send them to the position you desire. Also note in the software on the left side you can left click on any of the data channels and change it to read "current map." To verify your switch is working simply toggle the switch back and forth and note that it will change from Map 1 to Map 2.
If you're using a switch without LED functionality, as in the steps above, you can load the map you want for either switch position. If you want to use the ACC switch and wire it per KutenFLHX's diagram, I would put the lean map you'll be running most of the time in the open (LED off) position, as I would want the LED to be a warning that the rich map is enabled.
I don't have the LED working on my bike and I just remember what position toggles what map. OTOH I may connect a relay if I can find one that closes the primary circuit when power is not applied, the opposite of the standard auto relay as in KutenFLHX's post.
This will not work for Auto-Tune, which can function with a hardware switch but uses an entirely different procedure. For info on that, read my write-up here.