Lighted switches with a voltage rating effectively contain RLED and D1 from my schematic. The only reason they have a voltage rating is that they have picked the appropriate RLED rating to give suitable light output in the LED, D1. Such switches usually have common DC power supply voltage ratings of either 5V or 12V.
The data sheet for the switch should give some indication that this is what they have done. Ideally, you should see the LED and resistor in the switch schematic. If not, at least they should indicate the resistance.
Depending on how they have chosen the RLED value, you might be able to get away with a voltage difference as much as 2x, but you can't count on that. So, you might burn out a "5V" switch with a 9V powered CMoy, but you could probably get away with a 12V switch, no problem.
It is far better to get a switch with the LED in it only, without the resistor. Then you can calculate the RLED value as shown in my guide.
As for your "220-250V" number, I would guess that this doesn't talk about the LED path through the switch at all. That's going to be the voltage rating on the contacts in the actual switch. Such switches are sized for AC wall voltage applications. You can use them for low-voltage DC applications like a battery-powered CMoy pocket amplifier. Such switches are simply physically larger than actually required, in order to withstand the higher voltage.
As for the "pin 1-3" issue, it depends on the switch. There is no standard numbering system. You'll have to show us the data sheet if you want us to comment on specifics. I would guess that a lighted switch with only three connections wouldn't be suitable for this application, however. You'd want one with four connections, since you need the LED path to be separate from the switch path in a CMoy pocket amplifier.
Edited by tangent - 2/24/13 at 5:31pm