I'm writing this article out myself so that others won't be so confused as to what has actually happened with Manhunt 2, so I will write it out in a list.
[1] Manhunt 2 banned in UK - http://www.n4g.com/ClickOut.aspx?ObjID=46390
[2] Manhunt 2 banned in Ireland - http://www.n4g.com/ClickOut.aspx?ObjID=46480
[3] Rated "Adults Only" by ESRB - http://www.n4g.com/ClickOut.aspx?ObjID=46523
[4] Gamefly & Blockbuster refuse to stock Adult-Only games - http://www.n4g.com/ClickOut.aspx?ObjID=46730
[5] Nintendo will not allow Adult-Only Manhunt 2 on the Wii - http://www.n4g.com/ClickOut.aspx?ObjID=46775
[6] Sony will not allow Adult-Only games on their systems. -http://www.maxconsole.net/?mode=news&newsid=18233
[7] Most Likely that Australia will also ban the game following UK
It seems very likely that the game will have to be heavily edited otherwise it can't come out for any of the systems it is currently slated for. The other option is to cancel the game, but with the costs involved I think Rockstar will opt for editing the game.
Update
Just been informed by member alpharidley that Manhunt 2 has been banned in Italy too. Here is the link:
http://www.corriere.it/Primo_Piano/Scienze_e_Tecnologie/2007/06_Giugno/21/manhunt_videogioco_vietato_italia.shtml
Google translated version: http://www.google.com/translate?u=http%3A%2F%2Fwww.corriere.it%2FPrimo_Piano%2FScienze_e_Tecnologie%2F2007%2F06_Giugno%2F21%2Fmanhunt_videogioco_vietato_italia.shtml&langpair=it%7Cen&hl=en&ie=UTF8