unamednpc asked me to give some tips/pointers on g+ hangout gaming.
Sorry about it being in English.
I use Roll20. If you go to roll20.net you can register and then download the app in g+ hangout. It is free (although you can donate to remove the advertising/pause at the beginning.)
Roll20 has a layered play area for the GM with a map layer (complete with 'fog of war' to hide unexplored areas), tokens (you simply search for keyword like "goblin" and then drag the token to the tabletop. There is a dice roller, chat window, handout tool and even music/sounds
The GM should launch his campaign in roll20 in advance and upload any battle maps if you are going to use tokens/maps. Using the page tool (top of screen) you can create pages in advance. Be sure to add maps on the map layer. You can size them to match the grid by clicking on edit and align to grid.
When you add tokens, be sure you've switched to the token layer first. When adding tokens to represent the players, you have to edit the token and change the control to the player. I choose "ALL PLAYERS" for the player tokens to save time and allow people to help move tokens when needed.
In terms of G+ Hangouts, you start the hangout, invite your players, and then they are sent the invite and receive an alert to join. I find it best if everyone uses a headset, otherwise you might get some annoying echoes. If you have more than 3 players, hangout may start people in mute mode. I usually start the hangout a few minutes before game time to give more time to solve any connection issues.
With DS I use the dice roller on the tool bar rather than macros or code because we are simply rolling 20 sided dice.
If someone has poor bandwdith, hangouts now has a slider bar in the options to lower the bandwidth to help these players.
Good luck! Maybe play a few rounds without battlemat to get used to it, then bring on maps/tokens as you are ready.