Text (6th/7th/8th/9th+errata): 0/2. ; Whenever you cast an enchantment spell, you may draw a card. [Oracle 2009/07/08]
The ability is a triggered ability. Whenever you announce an enchantment spell, you immediately get the option of drawing a card as part of the triggered ability. [D'Angelo 1999/05/01] If the spell is later countered, you still get the card. [D'Angelo 2007/01/03]
Does not trigger on the moving of an enchantment from one permanent to another. [D'Angelo 1995/07/25]
Does trigger on enchantments that are cast as instants. [Duelist Magazine #16, Page 28]
Note - In Fifth Edition (and before) this card was of creature type "Enchantress". In Sixth Edition, it was a "Wizard". In Seventh Edition and Eighth Edition, it was "Druid".