CNET has written several times over the years about Audacity, a free, general-purpose sound-editing tool. I've known people who have used it to manipulate sound for podcasts and the like. But I'd completely forgotten about it until today.
One of my colleagues been looking for a tool to split recorded audio presentations into portions to go with the corresponding individual PowerPoint slides. I thought Apple's GarageBand might work, but he found it too opaque, and our office (like most) is PC-heavy, which would have complicated efforts to train other folks on how to do this job.
Then he downloaded Audacity, and it fit the bill perfectly. It let him see audio waveforms to figure out where the speaker stopped talking between slides, easily split the recording at those points, and clean up other extraneous noise from the track. At the same time, it didn't burden him with features more geared toward budding musicians such as built-in instrument sounds or an on-screen keyboard.
Reading through the documentation, I realized Audacity might be the perfect solution to a problem I've been facing myself. Today, I use Microsoft's Digital Media Plus Pack to record my LP records to digital format. But Microsoft discontinued that XP-only product when it released Vista and doesn't support it anymore. Worse, it records only to Windows Media Audio, which means I have to convert the files to AAC or MP3 before I can play them on my iPod.
But Audacity lets me record directly to MP3 using the LAME encoder, which I've already got installed for another audio-conversion program. Although MP3 offers sound at the same bitrate as AAC and WMA, hard drive space is now plentiful enough to encode everything at 320kbps, which is perfectly adequate for on-the-go sound.