There's an update for punkbuster. It's pretty easy, take a look at the info below.
For players that are having problems with not being able to connect, you probably want to take a look at this post.
Please update punkbuster manually via this link http://www.evenbalance.com/index.php?page=dl-bf3.php and these steps explained below.
To Manually update your local PunkBuster Security Files, choose "Save As" from your Web Browser's "File" Menu and explore to find your game folder and the subfolder called "pb". Save this file in that location ([game path]/pb/pbsec.htm or [game path]/pb/pbsecsv.htm). The next time you start your game, your PunkBuster will have the latest security information necessary to accept auto-updates from PB Servers.