I believe the best free speech recognition software is CMU Sphinx. It looks quite mature, though I have not used it. It is however more a research project than focussed on end users, so while it apparently works well, it's a bit of work setting it up; in particular, you will need to train it before using it.
Other software you might want to try:
http://en.wikipedia.org/wiki/List_of_speech_recognition_software
BTW, have you considered just listening to the messages using a small earplug if you're in a meeting. Might be the easiest way :-). Or, just have less meetings...