This says it requires these op systems
Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2
Printer pooling is available on XP Pro I just don't know if it works
I have never had any luck using windows printers and their drivers with Aloha anyway but it could work but I always thought printer pooling just printed to 1 of the 2 printers and then to the other if the 1st was offline or out of paper.
I did see a $99 box that said print to 2 printers simultaneously but you need a serial port and I don't know about that
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To set up a printer to print to multiple devices
Open Printers and Faxes.
Right-click the printer you are using, and then click Properties.
On the Ports tab, select the Enable printer pooling check box.
Click each port where the printers you want to pool are connected.
Notes
To open Printers and Faxes, click Start, and then click Printers and Faxes.
With printer pooling, the printers must be the same type of printer using the same printer driver.
The previous procedure assumes the printers you want to pool are already in the Printers and Faxes folder.