It definitely has some rough edges (caused my 770 to reboot when I tried stopping a recording from playing before it actually started playing) but it does work.

Check your Garage repo for it.

Gives you three formats to save as:
iLBC (typically a codec used in VoIP)
PCM A-law (aka au)
WAV (the format everyone knows and hates aka RAW)

For three identical (as far as my voice is consistent) 10 second recordings:
iLBC is the smallest with at 28 kB
PCM was about 4x iLBC
WAV was about 8x iLBC.

PCM was the clearest sounding.
iLBC was second best with good background attenuation but generally softer recording volume.
WAV had some clicking recording artefacts but did play with the normal audio player. Ther others played with the recorder only.

... and I would like to reiterate how I *hate* the way the 770 hides the file extensions and won't let you edit known types. I turn that off in windows the first chance I get. If anyone knows a hack to do so on the 770, please let me know.