It will be made easier if you also put them in a folder under the root called Music, since this is the default location in which the PS3 looks. I haven't tried going from an iPod, but the files themselves may not play due to DRM.
I don't know if there is a way to "share" iTunes so the rest of your network sees the files, but that would actually be the easiest way and wouldn't require you to load anything onto the PS3; just stream them from the computer. I have my laptop and my desktop and I stream from Windows Media Player 11 to the PS3 from both.