Here's cofirmation from Phil Harrison (during a gameinformer interview) of PS3 background downloading, which will be introduced post Firmware 1.6
GI: Well, it was very important, especially for me. There was all of this talk about the big update when the console hits Europe in March. You mentioned today, background downloads. Will that be part of it, and what are some of the other things that you have planned for that?
Harrison: The only thing I can talk about is that background downloading will be part of the 1.6 upgrade. There's a bunch of other stuff, but Kawanishi-san would kill me if I was to reveal all of the details.
Hit the link for more info