Cross Play support will allow multiplayer on both Vita and PS3.
At Sony's E3 2012 press conference, the company announced that PlayStation All-Stars Battle Royale will be coming to Vita, in addition to the PS3, when it launches later this holiday season.
Both versions will support Cross Play, which means up to four players can partake in multiplayer, with two on Vita and two on PS3, or three on Vita and one on PS3, or any other combination therein. Cross Save will also be supported, which means you can progress on either version and carry that progress over to the other version.
Also announced were two newly playable characters in PlayStation All-Stars: Nathan Drake from the Uncharted series and Big Daddy from the BioShock series.