VisualSubSync is a subtitle program using audio waveform representation as its cornerstone. SRT and SSA/ASS subtitle formats are supported. It also provides some tools to help improving the quality of your subtitle.
Audiere is a portable audio library which supports playing MP3, Ogg Vorbis, FLAC, WAV, IT, XM, S3M, and MOD files. You can use it from C, C++, Python, Java, Delphi, and any language that supports XPCOM (JavaScript in Mozilla, for example).