Theora's Bellydance Boutique
My first experience with Henna was with a henna artist from Pakistan.  She learned henna as a young girl from her female relatives.  She was about 21 and was a complete henna artist doing all the traditional henna designs with ease.  I learned a lot by watching her work. 
My next henna experience was at a Gypsy Caravan Tribal Quest.  The teacher was from Seattle.  The other students were all in the business of doing henna professionally.  I was a bit over excited by the whole experience and would have loved to have gone on in the company of those artists for a lot longer than one 2 hour work shop.  I took every crumb of information home from that workshop and studied and researched and found books and found really reasonably priced henna powder and other henna things.  Here are some of my findings.