Yes. WavPlayer can automatically be configured to be the default player for any of the sound formats including *.wav, *.dss, *.mp3, *.vox and many others. Select Options | Settings from the WavPlayer menu and click the Default Types tab. Click the check box in the Extension column for the File Type you wish to make WavPlayer the default player.
If you are still having trouble getting WavPlayer to be the default player and open automatically, please refer to this Knowledgebase FAQ: