The "5V" Arduino board is listed as requiring 7-12V input power. Since it also runs off of USB power, which actually is at 5V, I'm presuming there's some alternative point to connect power to that bypasses the regulator. I have a switching regulator providing 5V from a 12V supply for the rest of my design, and would prefer to have the Arduino run off the same supply.
Does anyone know where to connect such a supply and whether anything needs to be done to bypass the onboard voltage regulator?
The best way in my opinion is to just hack a spare USB cable and run your external +5vdc through the board's USB connector. As long as nothing is plugged into the external power connector or the Vin pin on the board, then the USB +5vdc power (if avalible of course) will power the board via the auto-voltage selector circuit.
Some people would just wire their external +5vdc regulated voltage via the Arduino's +5vdc pin, but I don't think that is the safest/reliable method.
Lefty
On the Pro boards which don't have a USB interface, would that be the +5 line on serial connector pins?
Didn't know that 5V board meant Pro board. Not sure of it's design, if it has a auto-voltage switch, etc. Perhaps you should wait for someone that has worked with a 5V pro board.
Good luck;
Lefty
you can just plug it into one of the +5v and ground connectors, course you know this but for future readers this is only for when you already have a proper regulated 5v power source (and not just a 5v wall wart)
Thank you both 
Sorry for the confusion not mentioning the specific board initially; I'm developing on the standard USB board but will wind up using the Pro variant for my final design because they're rather cheaper 