From here:
http://psforums.station.sony.com/ps/board/message?board.id=psnews&message.id=4323)
New players will be able to download the PlanetSide “Cannon Fodder” demo and will be able to play for free through Battle Rank 6. Once they complete BR 6, they will be able to continue to play the game, but will not progress to Battle Rank 7, On exit from the game, they will be taken to a website that will allow them to upgrade to a monthly subscription, which includes the base game, the expansion pack (Core Combat) and the Battle Frame Robotics (BFRs), the giant robot units. Depending on skill, it can take a player up to 30 days to complete BR 6, which will give them plenty of time to see many of the cool aspects of the game. Additionally, players can continue on in the game at Battle Rank 6 for the entire 12 month promotion period.
And, if you need a reason to get ready to DL planetside, a community member has also made a wonderful video (this is unofficial) of the game. See it here:
http://psforums.station.sony.com/ps/board/message?board.id=psdiscussion&message.id=802684&view=by_date_ascending&page=1)
P.S. If this article has been posted before, or if this is considered too advertisment like for the mods, just take it down. I won't have a problem with it.