I actually did acupuncture before my BFP to see if it would help in getting pregnant - it worked on the first try (well, I don't know for sure that it was the acupuncture, of course). In any case, I've continued to see my acupuncturist once a week since then, and I'll see her until the end of the first trimester.
I have had pretty awful morning sickness, and I do think the acupuncture has helped. I usually feel at least marginally better in the days following acupuncture, although the m/s gets worse in the couple of days before I go back. I also go because it is really relaxing, and she was really great in helping me feel better when I had a cold.
As I said, I go once a week, and it takes about 45 minutes total each time. She asks me how I'm feeling, takes my pulse, and then puts the needles in. I sit with the needles in for 30 minutes, and she'll put a heat lamp over the area that she is really concentrating on. Then she comes in and takes out the needles, and I am on my way.