So, the media player was release yesterday! That's great news, but I don't want to use and usb drive. How can you configure the PS4 to obtain my files from my pc via wi-fi?
You will need to run a DLNA compliant media server on another computer in your house to play your content from (your desktop PC would work fine). Once running it should just show up from the PS4 side in the list of devices you can play from.
I'm not going to recommend a specific media server package, but a quick web search for "DLNA Media Servers" should bring up the most popular programs for you to pick from.
Sony's announcement has screenshots showing what to expect.