The free open source Mediatoumb media streamer software can be used to turm a Linux, Apple Mac OSX, or FreeBSD PC into a media streaming center, allowing it to stream media to the PS3 or any other UPnP compliant media renderer.
http://mediatomb.cc/
Here are some instructions on how to do it with Gentoo Linux
http://volatileint.blogspot.com/2008/08/using-playstation3-as-media-center-with_30.html
but other Linux distributions like Fedora and Ubuntu have packages as well, and much of the configuration should be similar.
http://mediatomb.cc/pages/download
There is also an earlier post about a different DLNA server
http://www.howtoforge.com/set-up-a-linux-playstation-3-media-server-with-ubuntu8.04
http://mediatomb.cc/
Here are some instructions on how to do it with Gentoo Linux
http://volatileint.blogspot.com/2008/08/using-playstation3-as-media-center-with_30.html
but other Linux distributions like Fedora and Ubuntu have packages as well, and much of the configuration should be similar.
http://mediatomb.cc/pages/download
There is also an earlier post about a different DLNA server
http://www.howtoforge.com/set-up-a-linux-playstation-3-media-server-with-ubuntu8.04