SoundSlides does have the capability to accept uncompressed .WAV and .AIFF files and convert them to .MP3 for you. This method requires some very basic setup the first time to install an MP3 audio encoder called "LAME." Despite its name, LAME is the de facto open-source mp3 audio encoder on the Web.

When you first launch SoundSlides, it will ask you to either create a new project, or load an existing project. At this window, click on the help menu and select LAME Audio Encoder.

A window will appear on the right of the screen asking you to download and install the LAME audio encoder.

You must be connected to the Internet for this step to work. First click on the Download LAME button.

The LAME encoder will automatically be downloaded to your Desktop.

Next, simply follow the instructions by clicking Load LAME. An open dialogue box will ask you to locate the LAME file, which is appropriately titled "LAME" and should be on your desktop.

Once you have selected the LAME file, your version of SoundSlides will be ready to accept .WAV or .AIFF files for import. SoundSlides will convert these file types to .mp3s automatically upon import.

You will only have to set this up once. If for some reason you cannot load LAME, or the third-party server that hosts LAME is not working, you can follow this link to converting your files to mp3 using iTunes: http://multimedia.journalism.berkeley.edu/tutorials/audio/soundtrackpro/mp3convert/