The fake psychic was portrayed by Suzanne Krull
in the Season 3 episode "Tricia Tanaka is Dead".
Lynn Sarnoff also appeared in the Season 6 "sideways"
timeline as an employee in Hurley's temp agency.
I have written to Ms. Krull, requesting an autograph.
I'll update this post if/when I receive a response.
On a side note - Lynn Karnoff used Tarot cards in the "psychic
reading" she gave Hurley. A very talented artist and graphic designer,
Alex Griendling created a set of LOST Tarot cards that I am
drooling to own. He hasn't made them available for purchase yet,
but you can be certain that as soon as he does, I will be ordering several sets.