There are two ways to share files from a Mac to a PC.
The first is through Web Sharing.
To use Web Sharing, go to System Preferences, Sharing, and turn on Web Sharing. To access your files, open up a Web browser like IE or Firefox and type: http://<IPAddressOfYourMac>/~username/
The second way is through FTP. In the same window, check the FTP Access box.To get to your Mac files via FTP, open the command line in Windows and type: C:\>ftp <IPAddressOfYourMac>
Your Mac's IP address can be found under System Preferences > Network.