laptop cpu upgrade

Is it possible to upgrade a laptop's cpu? I am getting my 1st laptop soon here. Its on the way. I got an IBM thinkpad A20m for really cheap. It has a 500mhz celeron in it right now. I have see online other a20m laptops with pentium processors.

I can't quite seem to find specs on the laptop right now. Does anyone know where to look? Anyonne know off hand if I can upgrade the chip? Thx

Yes I know this is an old post..

BUT....

The best place for anyone who wants to find parts is Ebay. Just bought a power supply for $21 and there are batterys for around $30