OMG charlie... you're doing this ass-backwards. I have my XP Pro desktop connected to the printer. I share that printer from the printers section of the control panel. All I had to do on my XP Home laptop was add a printer and just browse the network for the printer. It found it and downloaded the drivers, no problem.
As for the MAC, I'm not sure how it works but I can't imagine it would be much different. You probably need some kind of software to do shares and whatnot, but it's not unthinkable. Also, setting the IP to static is done from the PC, not the router.