One more step
At least for me, it took me a bit to get the M$oft box up.
1) Share the folder on the PC. (I think "everyone" "read only" is default. Should work for moving files _to_ the iMac.
2) From the Mac. From the Finder menu Go->Connect to Server... (Cmd-K)
3) Enter the IP address of the PC *with smb://* in the first/front.
eg. smb://10.0.2.4/MyShare
or smb://10.2.2.4/C$ (if you want to sign in...)
4) Hit Enter or Click [Connect].
(Come to think of it, you may need to sign in anyway...)
5) Wait... A new browser window should open.
You will also notice all Finder windows now have your PC's folder as a "mounted". This is how you "log off" of your PC. Click the Eject button on your mounted drive...