Windows boxes (and OS/2) speak SMB, correct. Samba is a program used to speak SMB on non MS/IBM platforms, like OS X.
Sharepoints isn't required, but makes it easier in your case then learning how to edit the smb.conf file on OS X to share what you want. OS X by default only shares user folders via SMB when it is enabled, unlike Windows where it also shares the entire hard drive.
AFP is Apple's network file protocol, dating back to the days of AppleTalk networks. On OS X when enabled, it shared the entire disk to admin users, and user folders. There was an AFP client for Windows that Microsoft included, but it was dropped in XP and above, likely due to MS not wanting to update it to the OS X version 3 protocol.