You dont need a 3rd party app to file share. On the windows machine run network wizard. by default it creates a workgroup named MSHOME. select the folders that you want to share on the network on the share tab in the folder properties.
On your Mac click the Network icon in the finder. you should see an MSHOME folder and inside will be your windows machine. you dont need passwords to access the windows machines just click ok and proceed. for some reason i cannot always see my mshome folder from my mac. sometimes rebooting will do it or just opening and closing the network folder on the mac. its a little flaky.