Which is the software to find the songs information for free(other than tuneup companion)?

Media players have the option to find all the information for tracks . Chances are you have a few media players on your computer , load it up and go to options saves you from downloading more and more things .

mac or pc?

pc (windows xp and vista)

WMP or Teversity Link but seriously any media player will connect to the iinternet and source the information and album art .

Jaangle link searches automatically for album-art and artist-/song-information.
You can do it manually too (right-click a song and you’ll find it).

Thanks in advance

PicardTagger might be able to help fill in proper ID3 tags.

@johnpowell, @rebbel and @sandystrachan
As you’ve already answered for PC, which one would you suggest for a Mac?

VlC on a mac ?
I am no mac user so better for someone else to answer . And am not sure if VLC collects the information from net