Can someone tell me what is the best way to lay down speaker wire under carpet? I have approx. 2 20 ft. runs to my surrounds.

Is it better to go under both the pad and the carpet? Or better to go between the pad and carpet?

The best idea I've seen is to first lay down the pad, then cut a narrow channel in it just large enough to accomodate your wires, then lay the carpet down on top of that.

With this method, your wire won't be able to grind or roll around under the carpet, and you shouldn't see any bumps.

Under, as down the middle of the room ? Or would this be run along the baseboard ?
Baseboard is easy.. Just use a putty knife, and push the wire down into the gap between tack strip and wall, just under the baseboard.. Same procedure they use to lay the carpet.. Nothing needs to be removed, replaced, etc..
Under the carpet would depend on the subfloor material.. You lucky enough to have a basement, or crawl space, or is a cement slab ?

I prefer to go around the edges of the room and under the carpet. Unless you cut a channel, which is a lot of work and prohibitively permanent for renters, you're going to have a strane lump to walk across no matter what. Instead, you can usually wedge the cables under the base board, between the wall and the spike strips that hold the carpet in place. This is ideal in my mind.

Thanks for everyone's replies. I'm going to be running the wires along the edges of the room, near where the carpet and baseboards meet. Also, the surface under the carpet is a concrete slab.

You mean under the carpet nearest the baseboard, right? I tried the baseboard thing until I found out there were a few places I couldn't get the wire under. I got the flat wire from Radio Shack and ran it under the pad in a straight shot for my 3rd QS8. Nobody can tell it's there.