How to get printers working on Windows Vista and 7

Print servers need to have both 32- and 64-bit drivers for x64 systems. Ideally, they need to be the same version number (this appears to be mandatory for Vista to work). If you can download the drivers in both versions (e.g. for IGR's Kyocera C5020N and C5300DN) then you might be able to extract both drivers and then use the driver add facility on the print server machine to add the missing driver (i.e. on a x86 system install the x86 driver, then add the x64 driver using the print properties.
If the driver comes pre-packaged and insists on being installed, or if it's built into Win7 and you can't download it separately then you will need access to both a x86 and a x64 Win7 system. The procedure for an XP or Server 2003 print server is:
1. On one of the driver-donating systems, fire up the Print Management utility.
2. On the local print server drivers branch (right-click or Action) Add Drivers. This allows you to connect to Windows Update to get the up-to-date driver list. You probably want to install your desired driver locally to make sure it 'sticks'.
3. Add the appropriate print server if required.
4. In the drivers branch of the print server you can see all the installed drivers on the system (there are usually quite a few of these, as they include all the drivers installed by users connecting to network printers.
5. (right-click or Action) Add Drivers. Choose the appropriate architecture for the system you are using (i.e. you can't install x86 drivers using a x64 system, at least not without access to a x86 install disk and a complex extraction procedure).
6. At the list of drivers choose the appropriate one. I.e the one you may have installed locally already.
7. The driver files should now be uploaded to the print server. It always seems to hang for a bit at the end - it comes back eventually. You should now see the new driver in the list for the print server.
8. On the other driver donating system do the same. There should now be two drivers of the same name and version number, one for Windows NT x86 and one for Windows x64. In theory, Win7, Vista, XP systems etc should be able to connect happily to the printer. Yeah, right.
GP settings. Computer Configuration/Administrative Templates/Printers/Point and Print Restrictions. When [installing, updating] drivers for a new connection: Do not show warning or elevation prompt. Means users shouldn't have to be admins on Vista or 7 systems to install printers.
GP settings. Computer Configuration/Administrative Templates/System Driver Installation/Allow non-administrators to install drivers for these device setup classes. Allow Users to install device drivers for these classes: {4d36e979-e325-11ce-bfc1-08002be10318}. This may not be required with the above point and print setting. Need to experiment.
Problem with Canon iP4500 on a XP print server. This already had an existing driver. Added the two Win7 drivers. When printer was set to use old driver, Win7 x64 client tried to download it and failed. When set to new driver, didn't work properly (no ink level status etc) and XP systems complained. Could have set up two print queues, but solved problem by using spare GX280 with Win7 as new print server for this printer, with both x86 and x64 drivers. Works happily, except have to connect directly to connect to printer - AD listing gives error when connecting. Weird.
Couldn't connect to Kyocera FS-C5300DN on 2003 server with Win7 x86, despite pukka Kyocera drivers for both architectures being installed on server. May have been due to the bug described in KB982728. Installing the hotfix solved the problem in this case. Hotfix files are Windows6.1-KB982728-x86 and Windows6.1-KB982728-x64.