Friday's poker guide explains the rules and basic strategy of Razz poker.
"Have you ever played Razz? Razz is a variation on Seven Card Stud where instead of the highest hand winning, it is the lowest or worst hand that wins the pot. The lowest possible hand, also called “the wheel” is A-2-3-4-5, because straights and flushes don't count against a hand being low, and aces are counted as low. It is a refreshing departure from most poker games where achieving a high card hand is your goal."
The article can be found in the beginner guides sub section of poker guides area of the poker section in the sub tabs.