In RDP (Remote Desktop Protocol) version 7 a new feature is added that allows us to redirect the microphone to the remote machine and record the audio on the remote machine. This feature works only when connecting to Windows 7 or Windows Server 2008 R2 and if you have a Remote Desktop Client 7.0 which is a part of Windows 7 and was release as a standalone update for Windows XP and Windows Vista recently.
Anyway, for the redirection of the microphone device from your local machine to the remote Windows 7 or Windows Server 2008 R2 machine you need to allow the redirection. In Windows Server 2008 R2 you make the setting for the RDP-tcp connection in TS or RDS host settings but in the Windows 7 client there is no GUI for enabling redirection of the microphone. So on the remote machine you must start regedit.exe and go to
You need to make sure the value fDisableAudioCapture is set to 0 (1 is the default and means microphone redirection is disabled). Voila!