Um no, it is true, they won't charge you for per KB usage when downloading pix and flix messages because it goes through a proxy or something that tells them it is a pix and flix message. Just install nodata on your phone, get the per kb package, turn off the data connection with nodata when you are just using the phone normally, and turn it back on when using pix flix. The phone will connect like a normal data connection, and download the message but you will not be charged. I have used pix and flix and never found extra charges on my phone bill.
Download link:
http://www.modaco.com/content/Pocket...-FREE-Utility/
of course there are other ways to disable gprs but this has always been the easiest for me, and it is a tiny program you can install on the device.