WMA-MP3.com

Protected Music Converter is a software which allows you easily convert your protected music files to most frequently used unprotected formats (MP3, OGG, WMA, WAV). Supported input formats are: WMA, M4P, MP4, AAC, MP3, WAV, OGG, AU audio files, AIFF.

If you want to convert your WAV,WMA 9 or OGG files to MP3 format, this program is exactly what you are looking for. You can start conversion directly from Explorer by right-clicking on selected files and selecting "Convert to MP3" from context menu.