On Easyworship 2009 I could easily play a song in my library while another slide or Powerpoint was running.
Is that possible in version 6?

You can. It is actually designed to be able to attach an audio file to a song or presentation in EW. I will give you a link to a video that will show you how to do that. If you're wanting to play audio during a PPT like you did in EW2009, you can switch to Preview and Live view under the View menu and play the audio in the Preview window.
http://training.easyworship.com/support ... -to-a-song

Thanks Dan. I figured it out right before I read you post.
Gonna try making the switch from EW 2009 to EW 6 this Sunday and see how it goes. The new layout intimidated me after using 2009 for so long.