I can share files from both my Mac and PC..

To view files using PC from a Mac.. you need to enable Windows Sharing in the Sharing panel in System Preferences. Then you can browse your home folder from My Network Places (under the workgroup).

from windows, you can access your Mac at \\<your Mac IP>\<Account Name>

To view files using Mac from a PC.. I use the SMB server connection via Finder. From finder, select "Go" > "Connect to server.." > Type in "smb://<windows machine IP or computer name>/" then press connect.. it will request for logging in (when Windows is set to request for password to share files) and select a shared folder to mount it on the desktop..

A little troublesome, but it get things done..