OS X and Windows Printers now seems to work!!
Apple seem to have finally sorted out the whole OSX and Active Directory/SAMBA printers problem that has existed over the last few versions of OSX.
So now, in OS X 10.5.1 lists the printers on the AD server just fine, and allows you to simply select one, select the right driver, enter your username and password on the AD and voila, it works.
Just thought people may like to know, as the whole printer issue was a thorn in many people's sides for a while!