Music and sound (audio) files can be stored in a variety of file formats -- mp3, ram, avi, etc. Each file format has its advantages and disadvantages. Some formats are better suited for background playing, some create smaller files.
CDEX: is a free utility and can record and convert at different bit rates for compression. CDex is a tool to do all sorts of things audio related. Mainly focused on ripping and converting, things like turning your home Compact Disc collection into an mp3 collection on your hard drive become extremely easy. With built in support for many encoders you wont find any shortage of options for your media files.
GoldWave: is a shareware digital audio editor that has been around for 10 years. Version 5.0 is their latest release. After trying it out, if you like it, you can purchase it for $40.