I recently found out some of the mobile cpus can be replaced.
Yea, this you can usually figure out by model number. You can check the package of a chip on Intel's site. BGA is soldered on. PGA is socketed. I've been doing a lot of laptop repair lately and have been getting back in the knowledge base for this kind of stuff. Dell almost always uses socketed processors, Macbooks never do. Core 2 Vaio's I've worked on so far are socketed as well. HP DV6000 and DV9000 models were socketed as well.
I was confused by the new Core i# sockets for a minute there though..doh.
I still don't quite understand why Intel made a seperate socket for their high end processors, seems like a bit of a money grab as it makes you decide whether to cut out upgrade potential right at the start and forces you into starting over when you do want to upgrade.
On topic, I remember a few, expensive, Socket P desktop boards I think though..
I hate getting confused. :X