The Canon ZR90 works with a Mac. It uses a FireWire connection so you will need a suitable FireWire cable and a FireWire 800/400 adapter if the Mac only has a FireWire 800 socket.
No it is not.
yes
The Canon Pixma MX330 All-in-One Inkjet Printer with USB 2.0 will work on Mac.
Canon's download section lists all available downloads for Mac OS X (See links below). You can limit the listing to just the relevant Mac items by using the drop down menu at the top of the page.
yes
Canon accessories does not work on all models.
Yes most defenitley.
Mac uses an HD Canon Vixia. It is on his NickNews video.
If it's made for Canon, yes.
Canon supply a full range of Mac OS X drivers (See links below) for the MP610 scanner/printer. As long as you have the appropriate driver (last updated June 2009) for the version of Mac OS X you are running there should not be any problems.
You may need a new cartage, or more ink.
Any EF or EF-S lens will work with both the Canon 500D and 550D. So yes.