Oh, WOW . . . how, FUN, FUN, FUN!!! . . . OMG, this is a nice little trip down memory lane for me . . . my "Bollywood" phase/obsession that to this day, still lingers . . . but not quite as extreme . . . and let me tell you I didn't stop at the Henna, I had the full-on ear-to-nose, and mid-parted hair jewel down-to-forehead (I don't really know the name) and the hand jewels . . . and bindis galore . . . anyway, sorry, I got a little too excited there . . .
. . . but the best products to use, are the ones straight from the source . . . if you live in a major city, look through your directory guide for either an indian grocery or any indian store and inquire to see if they carry any henna products or if they can recommend a place where you can get it from, and see if they sell the tubes (I can't really tell you the brand that I've used as I honestly couldn't read it ~ it was recommended by the store owner). Anyway, those are the most potent, with stronger pigments . . . which means that your design will come out more prominent, and the ink stays longer on the skin . . .
if you so happen to come across one, a little trick I was taught for longer staying power: after you're finished with the design/application . . . take a lemon and squeeze the citrus over your hand, then wait till the henna dries a bit, then take a clear plastic saran-wrap (or whatever you use in the kitchen), and wrap it around your hand or arm, or wherever you applied the henna on, and keep it wrapped over night. (make sure it's wrapped tightly, and be careful not to smear your design). In the morning, wash off the henna, and Viola! This is what was instructed to me by my local merchant, and it worked for me in terms of lasting power (expect 2-3 weeks before the fading period begins). . .
Oh, and
Sephora Socialite, since you're from LA . . . if you're close by Cerritos/Artesia, or if you're near by there, make sure to drop by Pioneer Blvd . . . . it's Henna, Sari, Curry heaven! If you need directions, just PM me . . .

. . . . oh, lastly, in case some of you didn't know, "henna" is also good for the hair, very moisturing and deep conditioning . . . so, if your tresses are in need of some tender & loving care, and if you can get a hold of the "henna" shampoo, it does wonders . . .