This is a feature that a lot of people who liked to record Skype calls, record streaming audio and other various audio recording tasks used when on Windows XP, however upon using Windows Vista you cannot find the "Stereo" / "Line in" option in your Recording Devices.
Many people believed that Microsoft had got rid of it, however it's still there... it's just hidden. Here is how to get it working again.
1) Right click on your volume option down in the system tray and selected "Recording Devices".
You should now see something like this (usually... [read more]