Depending on what type of router you have you may not be able to connect the printer directly to your router. To share the printer on your PC with your Macbook, there's a few steps you have to follow...
These steps may vary a little, I'm using a Windows Vista PC and a 12" Powerbook G4 running OS 10.4, both connected to a Linksys WRT54GS router.
To share your printer through your PC, first you have to open up the Printers & Faxes section of your Control Panel, and then find the printer you want to share. Right click on that printer and go down and click on "Sharing." This will open up the sharing tab of the Properties menu. Now, depending on whether you are using Vista or XP, this will vary a little:
In Vista:
You first have to click "Change Sharing Options," then "Continue," then check the box that says "Share this Printer." You can then change the share name as you wish and click OK when you are done.
In XP:
You do the above, sans the "Change Sharing Options" as there isn't that box in XP, you can go directly to checking the "Share this Printer" and clicking OK.
After you have the printer shared on your PC, then you move to your Macbook.
Open up System Preferences, then go to the Print & Fax tab,
Click on the "+" icon, and then go to the "More Printers" button at the bottom of the window. This will bring up the "Printer Browser" window where you will see a few drop-down boxes and a list-pane. In the first drop-down box you want to make sure you have selected "Windows Printing" and then in the next drop-down box, you want to have "Workgroup" selected. This will then display a list of all the computers on your local network running Windows. Find the computer name that has your printer installed on it, double click on that computer, click on the printer. If it hasn't recognized the printer model, you may need to select it if its available as an option. Then click choose. You can then close the windows and you should be ready to print to your printer attached to your PC using your Macbook.
If you are running a firewall or all-in-one security suite, then you may need to open up the printer sharing or sharing port on the firewall software (or maybe the router), so if you have any trouble finding the printer with your Macbook, let us know
