Audio

Here are some links to resources to get you started adding audio assets and music to your game.

Music
Here are some places to get music from:

• 8Bit collective
• Newgrounds audio
• SampleSwap
• Jamendo – royalty free music

Sound Effects
Epic Sounds has a good guides on how to use sound in video games. Their list of how to create foley effects is useful too.

• Room tone audio can make your game locations feel more real.
• Boom Library has collections of high quality sounds for sale.
• FreeSound, which has – you guessed it – free sounds.

Audio Software

• fmod studio is free to use for indies and works well with Unity. The more you know about audio the better as this is professional grade stuff.
• Audacity is a free open source cross-platform editor
• Garageband is a Mac only music creator.
• fmod is a serious tool for sound designers.
• Here’s a great list of music and sound creation software

Troy of Darc Productions helped me find some of the above sources.