Praat
Free phonetic analysis software (Mac and PC).

ELAN
Free software for time-aligning transcriptions and audio or visual recordings.

Audacity
Free, open source software for recording and editing sounds.

Free XML Tools
Listing of free software tools for working with XML.

Open Source Mac
Free open source software tools for Macs.

Transana
Audio-visual digitization, management, and analysis software.

Transcriber
Tool for assisting the manual annotation of speech signals.

List of digital audio editors (Wikipedia)
Tool for digital audio editing.