Text (AQ+errata): {X},{Tap}: Untap X target lands. [Oracle 1999/09/03]
This is not mana ability. It is a normal ability and it will resolve along with other spells and abilities in its stack. The lands untap during resolution. [D'Angelo 2000/02/25]
You may untap your opponent's lands if desired. [Aahz 1994/05/03] This can be useful if Power Surge is in play.
Can be used on an untapped land. [Duelist Magazine #5, Page 22]
Vintage tournaments (see Rule 911) restricted this card from 1994/05/02 until 1997/10/01.
Legacy tournaments (see Rule 912) banned this card until 1999/04/01.
Extended tournaments (see Rule 913) have always banned this card.
Standard (Type 2) tournaments (see Rule 914) have always banned this card.
Note - The card type is "Artifact" and not "Mono Artifact". [Oracle 1998/07/01]