The million-plus downloads that a popular demo or map pack might receive could delight gamers, but rack up some expensive bandwidth costs. No problem: the publishers, who already pay a licensing fee to get their games on the two big platforms, could count on the platform holders — Microsoft and Sony — to pay the cost of piping that digital content to gamers.
That situation changed with the PS3 on October 1 of last year, when Sony implemented a 16 cents per Gigabyte fee to publishers for paid and free downloadable content, according to publishing sources familiar with Sony’s policy.
Game publishers are not happy about it.
http://multiplayerblog.mtv.com/2009/03/20/sony-now-charging-publishers-for-ps3-downloadable-content/