It's not freeware, but the program I've been using for several years is Total Recorder. I record radio shows during the day and listen to the resulting MP3 files when I work the night shift. It's a pretty easy program to use. It has a feature to automatically remove silence gaps, although I don't really use that feature. I mostly use the sound image feature to spot the commercial gaps and remove them manually. It takes me about 10 minutes to remove the commercials from about 6 hours of recordings. This shortens the original 6 hours down to about 3.5 hours, but it's all content. There are free trial versions available and the licence cost is less than $20 if it fits your needs.