Even old-fashioned grognards fond of their paperback games can appreciate some computerised help, when it comes down to PBEM (Play By E-Mail) or to mapping for instance. Here is a list of useful tools I have collected on the go:
PBEM and digital game boxes:
- VASSAL 3 (MAC friendly)
- Cyberboard 3
- Aide de Camp 2
- Zun Tzu
Mapping utilities:
- Hexdraw 1.1
- Hexographer
- Campaign Cartographer 3
- RPG Map Maker (Mac friendly)
The Australian Wargamer 
As far as virtual tabletop apps are concerned, don’t forget the newcomer, Battlegrounds Gaming Engine (aka BGE). It, too, is Mac-friendly. Here’s the link:
http://www.battlegroundsgames.com/nutshellbge.html