Okay, some spoilers here:




















Power Girl's off the JSA, and is no longer controlled by their editorial staff.  She's been made available to them for a short period of time to handle the transition, but is under another book's control---which is just loaning her to them.  Obviously, there are other plans for PG that don't involve the JSA.  Given that she's been under JSA editorial control the whole time her solo title's been in print, and given that having her appear in other books hasn't been a problem before---I would assume that there is another plan for PG, and one outside her own title.  
 
A team book, in other words.  The only team book she's been involved with in a major way aside from the JSA titles for a while has been the JLI: Generation Lost title.  There have been persistent rumors, (that seem plausible), that a JLI monthly title is in the offing once GL wraps.  Perhaps a few months later, to help get Flashpoint off to a start.  So to me, her new team books seems very likely to be a JLI monthly.  Anything less than a monthly, and she'd merely be loaned to them, without transfer of control from JSA.