The cover has a date of August 2006 but the indicia has a date of July 2006. The house ads and Dan Didio column indicate the July 2006 date is correct.
Superman [Clark Kent] (Earth-Two (Pre-Crisis)); Batman [Bruce Wayne] (Earth-2); Power Girl [Kara Zor-L; Karen Starr] (Earth-2); Huntress [Helena Wayne] (Earth-2); Flamebird [Supergirl; Kara Zor-El] (New Earth, cameo); Nightwing [Power Girl; Karen Starr; Kara Zor-L] (New Earth, cameo); Ultra-Humanite (Earth-2, villain); Brainwave (Earth-2, villain); Solomon Grundy (Earth-2, villain)
Reprints
in Supergirl: Candor (DC, 2007 series) ([May] 2007) [minus the credits and the note on the last page to read "Supergirl", and with page 21 split across two pages]