This shows the current tank, healing, or dps selections as well as the ability to select being a group leader. You can see that for doing a random Wrath heroic you will receive two Emblems of Frost as well as 68 gold.
Here you can select which type of random dungeon you'd like to do. At level 80, everything is available to you.
Here you can select specific dungeons. You'll also notice that it lists the level range for each. If you don't meet the level requirements for a dungeon, it won't display for you. I'll show more on that later.
You can close a group of dungeons with the minus to clean up the interface. This is helpful if you're trying to get your Outland dungeon achievements and don't want all of the others in the way when picking which ones you still need.
Now you're in the queue. At the top, you can see that the healer, tank, and dps options are now grayed out. You can't change any of your options without leaving the queue first.
This pops up when you mouseover the minimap icon for LFG. Here it shows how things are coming along with creating your group.
Here it will tell you what role you've been selected for as well as the rewards you'll be receiving for finishing the dungeon. This is your last chance to chicken out.
Once your group is ready in the queue and you've selected 'Enter Dungeon' you will get a box showing who you're waiting on and who has accepted by role. After everyone is ready, you are teleported directly into the instance it has randomly selected.
When you've finally been popped into your dungeon it gives you a fifteen minute debuff that prevents you from looking for another group. This is similar to the Deserter debuff given from leaving or going afk in an unfinished battleground to prevent hopping around for the 'right' group. Obviously, they want you to at least give the party fifteen minutes of your time before deciding if they're good or bad (no matter what gearscore says).
If your party has an enchanter of appropriate level in it, you'll be given the additional option of disenchanting any loot that drops. This roll appears to be the same as or possibly be below a greed roll. It's handy as selecting this option will automatically give the appropriate shard to the highest roller.
When running Azjol-Nerub we had some issues on the first couple pulls with threat. One of the mages decided he'd had enough and simply hearthed out of the instance (or maybe teleported). Suddenly, one of our mages was in Stormwind and afk. After downing the first boss and on our way to the next, we decided to boot him. After right-clicking him and selecting "Uninvite", the other people in the party got a vote popup if they wanted to boot him or not. As this isn't on live, we later recreated the process with our wonderful tree who healed my antics through the instance. As I don't want any bad connotations associated with him, I cleared his name out of this screenshot. Excellent healing and would pug with again.
I copied my level 63 druid over to the PTR to see how the interface worked with someone of lower level. As you can see, the rewards for lower level characters aren't quite in yet.
You'll notice that Wrath dungeons aren't even an option for my level 63 druid. Let's go take a look at the specific dungeons.
As you can see, it only lists the available dungeons for my level 63 druid as the ones it is high enough level for.
Unfortunately, this feature is only partially implemented at the moment. The interface does not completely work and isn't actually attached to any of the the LFG tools.