I am about to start one (maybe two) online table top games, so thought i would share some things. Some from my career in IT, others from what I have found.
Caveat: I am setting my games up with friends I already have, so the finding of a game is not an issue for me.
Software to handle the virtual tabletop. After going through all the trials of the paid software, and the fully free software, the best application to manage the games IMO is one called RoliSteam. It has not only the ability to do dice rolling, but also the ability to save chats, do secret rolls, have side conversations, open maps up, be drawn on by either the GM alone, or everyone can draw on it. Players can share pictures of their characters, and it has a built in music feature. If all the players download the music files, place them in the same location as the GM, the GM can play the music instantly on each players desktop. If they don't have the music, nothing is affected.
For voice comms, keep to a server in your country. Hosting one is viable if you are on a massive connection, but if you are playing with people outside your country, it does not matter what you use, latency will be an issue. In the case of TS and Ventrilo, they use similar codecs, and you can play with the settings to lower quality slightly to increase speed. However speed is a misnomer. A latency of 500 or less is half a second or less latency. Within a country I would expect latencies to be closer to the 120mark while playing, and using virtual software, meaning a 10th of a second roughly is the delay, and this is tolerable IMO.
Video streaming adds the level of being able to see others, however it also increases latency, and not everyone will have a webcam. If possible, and you can do it without too much effort or latency in broadcasting, then do it, but a better option might be to just open a tool like Rolisteam, upload a photo of yourself so the others can see, and use voice comms to do the talking.
Links: http://rolisteam.org/