Many desktop machines still do, and most of the modern motherboards in full or mid-tower size still have a PS/2 port or two, for laptops PS/2 support is almost non-existent.
I don't think that even thinkpad docking stations have PS/2 anymore. PS/2 support on modern laptops from non-obscure manufactures (leaving myself some wiggle room for whatever weird Chinese thing you might be able to buy on ebay) may very well be extinct.
That's the built-in keyboard, right? I thought those were USB for some reason, I guess not. I guess it would be more accurate to say that PS/2 connectors proper (6-pin mini-DIN) are likely extinct in laptops.
I think it was only common for a mouse, and the PS/2 keyboard controller was only designed to allow one keyboard and one mouse, meaning that the laptops supporting this try to merge the two inputs into one, which is error-prone, particularly when dealing with for example wheel mouse when the packet size changes. Raymond Chen has a blog post, and there is a comment from Ray Trent (then of Synaptics) for more about the problems:
http://blogs.msdn.com/b/oldnewthing/archive/2004/09/17/23083...
