Text (WL+errata): 1/2. ; {Tap}: Switch target creature's power and toughness until end of turn. [Oracle 2005/08/01]
As per Rule 613, power and toughness switching is applied after any effects that modify power/toughness. This means that even if new spells and abilities are played to modify power/toughness, they are applied before the switch. [D'Angelo 2006/01/01]
Note - This card was of creature type "Dwarf" until Oracle 2007/05/01 when it became "Dwarf Shaman".