The leading expert on Salvia is Daniel Siebert who first discovered the psychedelic potential of the active component called Salvinorin A. More information can be found here:
http://www.sagewisdom.org/
It is a fascinating plant, used by the ancient mexican indians for thousands of years, it is believed to be a cultigen, that is, a plant found only in the vicinity of people and never in the wild. Traditionally, the leaves are chewed, never smoked, and they are not effective when swallowed. It is associated with the virgin Mary, and is often called Ska Maria Pastora, she is said to speak to you through it. It is still legal, because our repressive governments haven't caught up to it yet, and also because it is not very suitable for recreational (party) use. It can be very challenging to the psyche in larger amounts. It is possible to concentrate the active ingredient, making an extremely potent drug.
Here is a complete book about it on the web:
http://www.lavondyss.com/donut/toc.html
Some words of warning...
"When the dose goes above 500 to 1000 mcg the effects can be very alarming. I have seen people get up and lunge around the room, falling over furniture, babbling incomprehensible nonsense and knocking their heads into walls. Several people have tried to wander out of the house. When the experience is over, they have no memory of any of this. In fact, they usually remember very different events. To an outside observer, people in this condition have a blank look in their eyes as if no one is present. It is also common for people to have a facial expression which is probably best described as being like that of a frightened animal."
There is also potential psychological danger with salvinorin A. I can confirm from my own experience that it can instantly obliterate any reference to sanity, logic, or even the idea of existing, and make one feel that either one's self or the entire universe has gone entirely and permanently crazy. Occasionally people who have been given salvinorin A, even highly experienced psychedelic users, feel that a bad0 joke has been played on them by whoever gave them the substance. One person who tried salvinorin A, who is quite experienced with DMT and most other psychedelics, remarked "It made DMT look like a water pistol, at a dose 50-100 times less."
My experiences with Salvia at higher doses (a pinch of 6x extract, smoked) were just like this, I got up and stumbled around, feeling the need to escape. Reality, as well as my own body were the same, splitting and stretching like caught in a vortex, repeating the same moments over and over, it was nightmarish. At one point I got to the door and opened it halfway, but it must have wore off enough for my instincts to react and shut it. There is no recognition of normality or normal dangers. I felt like I fused with the wall, then I broke through into a relatively calm space, only my head sticked out, there was a being there. The being noticed me with some irritation, like I had barged into his house without the proper courtesy or introduction. I came down 10 minutes later, still feeling totally scattered and shaking with fear. I went to my friends house and told him about it, and that helped, although I was still shaking two hours later. I have done 4 hits of acid at once before, and this experience made that look like a walk in the park. You need a sober person to help you with this, and make sure you don't get up and hurt or embarrass yourself.
I have had much better experiences than that with it, I like the tincture that Seibert sells, and chewing the leaves, it is a much more mild effect, and smoking the leaves isn't bad either, although it can be harder to achieve the same effects. On lower doses, you see and feel like you are in music or waves and patterns, you feel stretched and split in a pleasant way, and it might only last a minute or two.
I have a couple plants, they are easy to grow and propagate, and have an unusual square stem.