Karen - I use Emerita by Progest - the single packets. I found mine at Whole Foods but read all the reviews on amazon. There is a list on Dr. Lee's website of suggested natural progesterone creams.
I'll admit I was skeptical. I am with Dr. Check doing natural cycles but not every month. I tried it in hopes to keep things regular in between visits. The first month I tried it I did one packet a day (20mg) before bed. I did not get AF but following the suggestion I waited again another 14 days and started the progesterone again this time with 40mg. I got a regular AF flow 2 days after stopping and actually grew a follicle that cycle. I did use estinyl that cycle as well. However I had used estinyl previously on 2 very long cycles and I never grew a follicle. My instincts are telling me I need the progesterone every month to keep regular especially since I am not going to grow a follicle each time. Hope this helps.