Ok it's not for everyone but if you want one it's very cheap, it's the cheapest i have seen.
£33 on Amazon
Belkin Bitronics AutoSwitch Kit switch - 2 ports
Device Type: Switch
Form Factor: External
Ports Qty: 2 x parallel
Manufacturer Warranty: Limited lifetime warranty
The Bitronics Data Switch is completely plug-and-play, requiring no software installation. Simply attach the cables and you're done! Connect both your laser printer and scanner, your QuickCam and Zip drive, or your tape backup and inkjet printer. It's that easy! It is also fully reversible, allowing connection of two PCs to a single parallel port device. The Bitronics Data Switch is the easiest, safest way to share parallel port devices!