The icons are not very useful as they show differently according to which player is set as default on you machine. You need to use the "type" column. If this doesn't show right click on the search columns header bar and select "type" this will show mp3, wma etc.
Most files found on limewire are mp3, and these will certainly play in iTunes, and really it is best imo just to go for mp3s.
I hope this is helpful
and the apology is unnecessary lol