My fiance found this tour company online last fall, because he knew I was dying to tour the vaults. We chose the historical tour as opposed to the ghost tour (next time we will do the ghost one). We actually went to Edinburgh in January of 2011 but the date was not available for me to select on here.
They have you meet at a landmark on the Royal Mile, and the tour guide takes you from there. I really wished I had remembered his name, our tour guide was the best. Aside from being informative, and full of knowledge, his story telling is what made the tour stand out. To this day, my fiance and I still talk about the tour or comments the guide made. He also went around and introduced himself to each of us asking us where we were from. There's just a personal touch here that you don't find as often as you'd like. When we go back to Edinburgh, we are booking at least one or two tours with this company including the haunted one!
If you are doing the tour of the vaults, please be prepared to walk, wear sturdy shoes or you'll probably go flying. It's an OLD city! Once you are in the vaults, it's dark and closed off so if you are claustrophobic, be warned. (I did not think it was that bad) also make sure you dress appropriately so you don't freeze half to death if you are there in the winter like we were.