Free Virtual Gaming Tables:
OpenRPG
Probably has the biggest user base of any VT app.
OpenRPG+
This site hosts the development version of OpenRPG.
MapTool
Java-based. Developers are actively enhancing this program regularly.
Gametable
Java-based.<{br />
Online Pen & Paper World
Windows-only.
Tri Axe Dungeons & Dragons Chat
Windows-only.
Interactive Dungeon
Windows-only
D20Map
Windows-only.
V-FORT
Windows-only at this time.
Dave's Flash Mapper
Possibly still in development.
YumiChat
Windows-only server, Windows and Mac clients.
RPG Manager
Windows-only. v2.0 is in development, and screenshots for it are now available.
Playing Fields
Java-based.
Dices
Windows-only.
RPGui
Windows-only.
TRIS
Text-based only.
AjaxVTT
Linux-only. Not for the technically-challenged.
Battle Map v2.0
Flash-based, runs in your browser.
RPG Tonight
Runs in your browser.
Tabletop Mapper
Windows-only.
GlitterComm
Windows-only.
Dungeon Helper
Windows-only.
Avalomhilly
Windows-only.
MAPPING SOFTWARE
Dundjinni
Produces beautiful maps. Highly recommended.
ProFantasy
The makers of Campaign Cartographer 2 & 3, and other mapping programs.
AutoREALM
A great free tool.
RPGMapMaker
Mac-only
MapCrafter
DungeonForge
MapMaker
zMapper
Benny's Dungeon Map Maker
StoneSword.com
Free mapping software that works right in your browser.
Dungeon Crafter 3
Hexmapper
Registration to the Yahoo Group is required to download the program.
FREE Maps/Tokens
RPGMapShare.com
A highly recommended repository of maps and artwork for RPGs. This is Steel Rat's new site, which replaces his old image gallery.
Dundjinni's Free Download of the Week
VOICE CHAT APPLICATIONS
Skype
Ventrilo
Gizmo
Ineen
YakForFree
TeamSpeak
(Note: the unofficial and unrelated "TeamSpeex" Mac client is still in beta)
OTHER VIRTUAL TABLETOP PROGRAMS
Commercial Programs: Be forewarned...
Battlegrounds: RPG Edition
That's what the rest of this site is about. I'm just including it to make the list complete.
Fantasy Grounds
Windows-only. Many people like the look and feel of this app, and the 3D dice rolling.
KloogeWerks
Java-based. Steep learning curve, but powerful.
ViewingDale
Windows-only.
D20Pro
Java-based, 2-week free trial license.
ScreenMonkey
Only the GM must pay. Players play free, using their web browser. The GM app is Windows-only. A Lite version is available for free.
RolePlayingMaster
Windows-only.
GRiP
No longer developed, but a number of people still use it and there seems to be a user community that supports it.
iTabletop
Windows-only. Features built-in voice chat, and streaming video/webcam support.
EpicTable
Windows-only. Not yet released.