I have a video for which I'd like to convert the audio codec to AAC 320 kbps / 44.100 kHz. What would I use for ffmpeg switches such that all the video settings and codec remain the same, but only the audio codec and settings change?

Here's my video:

$ ffmpeg -i Winnipeg.rb\ Scala-Talk.mov FFmpeg version SVN-r25375, Copyright (c) 2000-2010 the FFmpeg developers
  built on Oct  6 2010 13:02:41 with gcc 4.2.1 (Apple Inc. build 5664)
  configuration: --enable-libmp3lame --enable-shared --disable-mmx --arch=x86_64
  libavutil     50.32. 2 / 50.32. 2
  libavcore      0. 9. 1 /  0. 9. 1
  libavcodec    52.92. 0 / 52.92. 0
  libavformat   52.80. 0 / 52.80. 0
  libavdevice   52. 2. 2 / 52. 2. 2
  libavfilter    1.48. 0 /  1.48. 0
  libswscale     0.12. 0 /  0.12. 0

Seems stream 0 codec frame rate differs from container frame rate: 2000.00 (2000/1) -> 10.00 (10/1)
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Winnipeg.rb Scala-Talk.mov':
  Metadata:
    major_brand     : qt  
    minor_version   : 537199360
    compatible_brands: qt  
  Duration: 01:10:53.00, start: 0.000000, bitrate: 283 kb/s
    Stream #0.0(eng): Video: h264, yuv420p, 800x598, 94 kb/s, 10 fps, 10 tbr, 1k tbn, 2k tbc
    Stream #0.1(eng): Audio: adpcm_ima_qt, 22050 Hz, 1 channels, s16
    Stream #0.2(eng): Audio: adpcm_ima_qt, 22050 Hz, 1 channels, s16
At least one output file must be specified

Many thanks in advance! One with with ffmpeg I've never been able to grok is how to just "tweak" files without having to regurgitate every little setting for things you don't want changes.