OS X Mountain Lion has the ability to allow others to connect to a printer connected to your Mac. As long as they are on your local network, then other Mac and Windows computers are capable of sharing your printer.
In normal Apple style, sharing your printer with another Mac computer couldn’t be simpler.
- Navigate to /Applications/System Preferences, and then select the “Print & Scan” Preference Pane option.
- If required, authenticate as an “Administrative User” by clicking the Lock icon, in the lower left corner.
- Select the Printer you wish to share in the sidebar.
- Select “Share this printer on the network”. (OS X Mountain Lion automatically enables the Printer Sharing Service in the Sharing Preferences Pane. Its default is all users can share the printer.)

To share with a Windows Computer however things have changed in Mountain Lion. Apple have removed the option to share your Printer with Windows Computers. Previously in OS X Lion you could enable file sharing over SMB and then choose which Users could connect.
To share with a Windows Computer in OS X Mountain Lion you will need to set up Printer Sharing as above and then on your windows computer you will need to download and install “Bonjour Print Services for Windows”. There are a few system requirements which you will need to check before attempting to install.
Bonjour Printer Services for Windows gives you the ability to discover and configure printers shared via Bonjour (UDP Port 5353). This will therefore allow you to connect to a Printer that is connected via USB to your Mac.