Resurrected creatures are subject to summoning sickness (see Rule G19.39). They cannot be tapped to attack or to use an ability on the turn in which they come into play. [Mirage, Page 14]
Treat the creature like it has been played from your hand but with zero applied to any 'X' in the mana cost. So, a Resurrected Clone would get to choose a creature to copy and a Resurrected Rock Hydra would have zero heads. [PPG Page 92]
You can Resurrect a creature which was discarded from your hand and was therefore never in play. [D'Angelo 1994/04/01]
Extended tournaments (see Rule 803) banned this card from 1999/10/01 until 2006/10/20 when it became part of Time Spiral.