[z3n]

The easy-easy way?
If you are using windows, just use "Sound Recorder", which is probably located in your Start Menu -> Accessories -> Entertainment -> Sound Recorder (depending on which version of windows you use).
With that, you will be recording WAV files, which are fine for burning to Audio CD.

However, for better compressed files, such as MP3s, you will need software (such as Cool Edit, ellued to in previous reply), which will also give you the ability to clean up the sound file using noise reduction.

[bird4four4]

I've tried that. Sound recorder has a 60 second limit. I have some home recording software called power tracks that I use. For free I've used goldwave.