Woops...misunderstood the question (that's if you want to share out to Windows PCs from the Mac)
Actually, all you need to do to view your shared folders on Windows PCs is to head to the menu bar and select Go-->Connect to Server. The Mac should start searching for available computers on the network, or you could manually type in the ip address of the machine in the following format: smb://<ip-address-of-windows-pc>