Indeed not yet the alternative to mp3. But this is due to the hardwarefact of mp3-players not being able to read the format,
And still lots of mediaplayers needing a plugin.
Regarding soundquality and filesize there's not that much difference.
But there are more aspects to OGG:
Better performance in dynamics and panorama. It can handle multichannel formats.
It's open source, while Fraunhofer has the copyrights of the mp3-format.
And adding to Jojo's tip a FLAC <--> WAV converter : Flacdrop