Text (SM): If you would draw a card, draw two cards instead.
This is a replacement effect that alters other draws. [D'Angelo 2008/05/17]
It does affect your draw during the draw step. [Shadowmoor FAQ 2008/04/21]
If you would draw more than one card from something else, this replaces each of those card draws with two draws, effectively doubling you number of draws. [Shadowmoor FAQ 2008/04/21]
The effects of more than one of these are cumulative. If you have two, you will end up drawing 4 cards, and if you have three it will be 8 cards. [Shadowmoor FAQ 2008/04/21]