I'd recommend trying to configure CUPS directly via localhost:631 in a web browser. You don't really need to configure samba much (certainly don't need swat) to print to an XP printer - you will for file-sharing though.
What are you wanting to do with pdf's? Most Linux applications can print to pdf and there are several command line tools for converting to and from pdf.
If you're really worried about security it might be worth getting the router to forward ports to a non-existant IP address on your local network.
Oddly enough my router sometimes responds to exrternal pings, sometimes it doesn't...
I'd suggest looking at the pinned thread at the top of this forum and following the various bits of linked advice. The post back if you're having trouble.
The router may have port forwarding turned off - you might need to play around with which ports to allow through. It may also have a firewall so it's probably worth checking that.
What does iwconfig say after you've told it the correct ESSID to use?
You've probably already done this, but please ensure your firewall on the machine is turned off too.
Did you not install ndiswrapper from source? If so it wouldn't be in the rpm database.
I'm getting a bit lost as to what you're trying to do now. Why is there a rt2500 driver being loaded in ndiswrapper?
It's worth checking the chipset number (from lspci -n) against the database just to be sure (unless thats what Ian did ) - sometimes manufacturers change chipsets bbut don't change the label on the box.
Some of the mandriva ndiswrapper rpms seem to be broken, if you can't get it to work it's probably worth installing from source - see the pinned thread at the top of this forum for more details.
Basically you can use any of the tools that you'd generally use to manage multiple users on a system. Try looking at w and last (try last -20 to see the last 20 logins). w will show you a little of what the user is doing at that time too.