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The MP610 does not have Wifi capability built in however Canon does offer a print server solution you would have to purchase in order to do this using Wifi.
See the Silex Wireless Print server at the link below toward the bottom of the Accessories list:
If you have another PC available then another option would be to connect the printer to the other PC and share the PC over the network. Then the laptop could print to the printer over wireless through the PC sharing the printer.
Yes as long as you share the printer on the Mac. You can then follow the instructions at the link below in order to connect to the printer from the XP.
Make sure that when connecting to the printer and it asks for a username and password XXXXX you use the username and password XXXXX an account on the Mac.