You should make sure that you are telling iTunes to rip the tracks in a format that other players commonly recognize and play - namely .mp3. Before you begin ripping the CDs, be sure to open Edit->Preferences in iTunes, select "Importing" and be sure the encoder is set to .mp3, and not AAC.Once you've done this, you'll be ripping your tracks in a format that is sure to play in just about any other device. Also, iTunes can also convert them back to .wav format and burn a CD that any CD player will recognize.
mp3.about.com