MP3 PLayer Installation on UBANTU

I have installed Ubantu Linux in New Compaq Celeron LapTOP-- Dual Boot XP and Ubantu. All seemas to be ok. But MP3 file not working. Tried to pwn load some MP3 player from we. I am not sure --ways to install packages. Please Help. G.Krishna Prasad. 091-9444956419