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The Canon wireless printers support infrastructure mode. This mode often consists of a wireless access point, such as an Airport Extreme. Connecting directly to your Mac is known as ad-hoc and the Canon wireless printers do not support this mode, as you have found.
However, if you were to enable Internet Sharing on your Mac, this effectively turns the Mac into a wireless access point thus allowing the wireless printer to connect directly to it. Note that when you do enable Internet Sharing, and you are using either an Ethernet connection or USB wireless device, you will want to configure the share with a password so that other computers cannot use your Internet. Also, if you are not connecting the MBP to the Internet at this site, you can still enable Internet Sharing on the MBP so that the MP560 can connect to it. Simply select the Ethernet port even if it is not being used as the port that is supposedly connecting the Mac to the Internet.
Have a look at this article for more information on OS X 10.6 Internet Sharing.
http://docs.info.apple.com/article.html?path=Mac/10.6/en/8156.html
Pahu