Laptop processors

Hey all...

What is a P-M? Is it different to a Pentium 4 - Mobile? I'm looking to buy a cheap laptop, and am slightly confused by the specs on ebay.

I've been advised to go for a P-M if at all possible, due to them being pretty fast for the clockspeed, and the P4's are power-hungry and get hot easily... how true is that?

Also, what clockspeed do the P-M's range from? I guess I'm pretty safe if I go for a Centrino, right?

I've also heard something about how Pentium M proccessors have a built-in function to actively seek out any nearyby wireless signals, is this true?