Audacity…it’s FREE and available on both Mac & PC.
Find the version you need and download it here: http://www.audacityteam.org/download/
Once you have it, you can record, AND/OR edit your sounds and music.
Here are some basic tutorials to get you started:
Here is an older video of mine that covers much the same info as the one above.
One of the more interesting things you can do is change the pitch of a voice (your voice?) from female to male or vice versa. Here is a very quiet video, showing use of the pitch effect. You can experiment with 10 – 20%, or go crazy and create “chipmunks” or “monsters”. Just watch out for too much distortion!!