With Windows 7, you can more easily share files and printers across a network via the new HomeGroups feature. HomeGroups lets you connect to files and printers with a group password--if all the PCs have Windows 7. But I'll show you how to get your Windows 7 PC to play nicely on a network that also has Macs and XP/Vista PCs.
Set Up Windows 7 to Share a Printer
Open Devices and Printers from the Start Menu, and double-click your printer. Pick Customize your printer, and click the Sharing tab in the following window. Select the Share this printer checkbox.
Unless you're connecting a bunch of similar PCs, I recommend skipping the option to download additional printer drivers on the host system. Just take a moment to configure everything once on each client. With different combinations of 32- and 64-bit Vista, Windows 7, and XP PCs, it's more hassle than it's worth to try to plan ahead here. Approve the options and close the Properties window.
Share a Printer From Vista and XP
It's a similar process in XP. Open the Printers and Faxes control panel, and right-click your printer. Click Share this printer, and click OK.
Connect to a Shared Printer in Windows 7
In Windows 7, open Devices and Printers from the Start Menu, and pick Add a printer. Click the second option to add a network printer, and pick your printer from the list. Click Next, and wait for the printer driver to be located. If you want this printer to be the default printer, make the necessary selection, and click Finish.
Windows 7 couldn't automatically locate the printer driver for my aging-but-strong Epson Stylus Photo R1800 on my network. If you face the same problem, manually download the driver from the printer company's Website, and browse to it when prompted.
If that still doesn't work--it didn't for me--try installing the printer driver before trying to connect to your designated network printer. When I did this, Windows 7 afterwards had no problem reaching my network printer.