First off het Sharepoints...
http://www.hornware.com/sharepoints/
It will allow you to set What you want to Share with Whom, and/or Groups, in both AFP and SMB.
From Macs... typing afp://ipaddress into any Browser... IE,Safari/Firefox, should bring up the User/Password box, then present which Shares that person can see/use.
I presume smb://ipaddress works on/from a Windows® browser, but since all my PCs are switched over to Linux, I cannot attest to that facet.