Thanks for telling me what will actually be helpful instead of just telling me to install an updated alsa package (not helpful).

This is the amixer output for the working config:

Simple mixer control 'Master',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined penum
  Playback channels: Mono
  Limits: Playback 0 - 64
  Mono: Playback 48 [75%] [-12.00dB] [on]
Simple mixer control 'Headphone',0
  Capabilities: pvolume pswitch penum
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 64
  Mono:
  Front Left: Playback 64 [100%] [0.00dB] [on]
  Front Right: Playback 64 [100%] [0.00dB] [on]
Simple mixer control 'Speaker',0
  Capabilities: pvolume pswitch penum
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 64
  Mono:
  Front Left: Playback 64 [100%] [0.00dB] [on]
  Front Right: Playback 64 [100%] [0.00dB] [on]
Simple mixer control 'PCM',0
  Capabilities: pvolume penum
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 255
  Mono:
  Front Left: Playback 253 [99%] [0.40dB]
  Front Right: Playback 253 [99%] [0.40dB]
Simple mixer control 'Front Mic Jack Mode',0
  Capabilities: enum
  Items: 'Mic In' 'Line In'
  Item0: 'Mic In'
Simple mixer control 'Line Jack Mode',0
  Capabilities: enum
  Items: 'Mic In' 'Line In'
  Item0: 'Line In'
Simple mixer control 'Mic Jack Mode',0
  Capabilities: enum
  Items: 'Mic In' 'Line In'
  Item0: 'Mic In'
Simple mixer control 'Beep',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined penum
  Playback channels: Mono
  Limits: Playback 0 - 3
  Mono: Playback 0 [0%] [-18.00dB] [on]
Simple mixer control 'Capture',0
  Capabilities: cvolume cswitch penum
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 15
  Front Left: Capture 12 [80%] [18.00dB] [on]
  Front Right: Capture 12 [80%] [18.00dB] [on]
Simple mixer control 'Capture',1
  Capabilities: cvolume cswitch penum
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 15
  Front Left: Capture 0 [0%] [0.00dB] [off]
  Front Right: Capture 0 [0%] [0.00dB] [off]
Simple mixer control 'Input Source',0
  Capabilities: cenum
  Items: 'Mic' 'Front Mic' 'Line'
  Item0: 'Line'
Simple mixer control 'Input Source',1
  Capabilities: cenum
  Items: 'Mic' 'Front Mic' 'Line'
  Item0: 'Mic'
Simple mixer control 'Mux',0
  Capabilities: cvolume penum
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 3
  Front Left: Capture 0 [0%] [0.00dB]
  Front Right: Capture 0 [0%] [0.00dB]
Simple mixer control 'Mux',1
  Capabilities: cvolume penum
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 3
  Front Left: Capture 0 [0%] [0.00dB]
  Front Right: Capture 0 [0%] [0.00dB]

This is the non-working config:

Simple mixer control 'Master',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined penum
  Playback channels: Mono
  Limits: Playback 0 - 64
  Mono: Playback 48 [75%] [-12.00dB] [on]
Simple mixer control 'Headphone',0
  Capabilities: pvolume pswitch penum
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 64
  Mono:
  Front Left: Playback 64 [100%] [0.00dB] [on]
  Front Right: Playback 64 [100%] [0.00dB] [on]
Simple mixer control 'Speaker',0
  Capabilities: pvolume pswitch penum
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 64
  Mono:
  Front Left: Playback 64 [100%] [0.00dB] [on]
  Front Right: Playback 64 [100%] [0.00dB] [on]
Simple mixer control 'PCM',0
  Capabilities: pvolume penum
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 255
  Mono:
  Front Left: Playback 253 [99%] [0.40dB]
  Front Right: Playback 253 [99%] [0.40dB]
Simple mixer control 'Front Mic Jack Mode',0
  Capabilities: enum
  Items: 'Mic In' 'Line In'
  Item0: 'Mic In'
Simple mixer control 'Line Jack Mode',0
  Capabilities: enum
  Items: 'Mic In' 'Line In'
  Item0: 'Line In'
Simple mixer control 'Mic Jack Mode',0
  Capabilities: enum
  Items: 'Mic In' 'Line In'
  Item0: 'Mic In'
Simple mixer control 'Beep',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined penum
  Playback channels: Mono
  Limits: Playback 0 - 3
  Mono: Playback 0 [0%] [-18.00dB] [on]
Simple mixer control 'Capture',0
  Capabilities: cvolume cswitch penum
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 15
  Front Left: Capture 12 [80%] [18.00dB] [on]
  Front Right: Capture 12 [80%] [18.00dB] [on]
Simple mixer control 'Capture',1
  Capabilities: cvolume cswitch penum
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 15
  Front Left: Capture 0 [0%] [0.00dB] [off]
  Front Right: Capture 0 [0%] [0.00dB] [off]
Simple mixer control 'Input Source',0
  Capabilities: cenum
  Items: 'Mic' 'Front Mic' 'Line'
  Item0: 'Mic'
Simple mixer control 'Input Source',1
  Capabilities: cenum
  Items: 'Mic' 'Front Mic' 'Line'
  Item0: 'Mic'
Simple mixer control 'Mux',0
  Capabilities: cvolume penum
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 3
  Front Left: Capture 0 [0%] [0.00dB]
  Front Right: Capture 0 [0%] [0.00dB]
Simple mixer control 'Mux',1
  Capabilities: cvolume penum
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 3
  Front Left: Capture 0 [0%] [0.00dB]
  Front Right: Capture 0 [0%] [0.00dB]

The mic in question is the one built into the netbook (the internal mic, as the title of the bug report indicates). It is not a mic I plug in via USB or some other port. It's part of the netbook.

Please let me know if there's any other information I can provide that will help get this fixed for Natty. Thanks!