I did not see that there was a response on Apple's support site that adds to the previous post I mentioned. Combing the steps from the two posts, I was able to get our W7250 to print from Mac OS X 10.5 Leopard.
Here are the steps I took to get a networked Canon imagePROGRAF 7250 to work with a Mac running Leopard :
1. Download garo34 print driver from Canon's support site here
2. Download the iPF610/iP710 Leopard print driver from Canon here
3. Double-click on the garo34_osx.hqx file that you downloaded.
4. A folder named Driver is created; open it and double click on "GARO Installer for X".
5. Enter a name and password of an administrator account on your Mac and click OK.
6. When the GARO Installer for X window appears, click on Continue.
7. Click Continue.
8. Click Continue.
9. Click Agree.
10. Click Install.
11. When the installation is complete, click on the Restart button.
12. When your system has restarted, double-click on the iPF610_710_Driver_OSX_10.5_Ver1.10.hqx file you downloaded.
13. A folder named iPF610_710_Driver_OSX_10.5_Ver1.10 is created; open it and double-click on "iPF Driver Installer X".
14. Enter a name and password of an administrator account on your Mac and click OK.
15. When the iPF Installer X window appears, click on Continue.
16. Click Agree.
17. Click Install.
18. When the installation is complete, click on the Restart button.
19. When your system has restarted, click on the System Preferences icon on your Dock or select System Preferences from the Apple pull-down menu.
20. When the System Preferences window appears, click on the Print & Fax icon.
21. Click on the + Button underneath the Printers column.
22. Another window will appear; click on the "More Printers" icon.
23. A drop-down window appears; select Canon IP (GARO) from the pull-down menu if not already selected.
24. In the "Printer's Address:" field, enter the IP address of your Canon W7250 printer (e.g. 192.168.1.2).
25.In the "Queue Name:" field, enter a name for your printer (e.g. W7250).
26. Click on Add.
27. The W7250 is now your default printer. If you want another printer to be the default, change it in the Print & Fax preference pane.
I hope this solves your problem and you found the instructions helful.