Hmm... I think playing two audio files in openal is quite easy. OpenAL just works with buffers and sources, with wich you can play things simultaniously. The hardest part is getting the data into the buffers without any hickups i guess (in case of streaming audio). Playing should go perfectly well.

Are you able to play 2 wave files simultaniously? Or is your problem time-related (you want to start playing both at exactly the same time)?