Here is where being old counts for something - lol! I used run run a BBS on my Vic20 in the old days and helped a friend on this TRS80 and later helped out with NYMUG's First Class BBS (I still have it somewhere...). SecondSite BBS Software?

There might be a download in this ancient archive - http://software.bbsdocumentary.com A lot of BBS software is archived there for educational purposes.

Scroll down to Apple, then Macintosh and it should be there. I see a link to a description page but did not test out the link.

There are many BBS Software that now links up to the net. ELEBBS and WildCat for the PC, FirstClass and Pancake (which is not on the list) for the Macs are a few off the top of my head.