How to get a free and approximate audio transcription via YouTube’s automated transcription:
1. Use the free Audacity or other desktop audio software to split your .mp3 into segments of less than 15 minutes each. I assume that’s still the limit. Or make it whatever time-limit YouTube sets on uploads in future.
2. Upload the .mp3s to YouTube as a “Public” video via TunesToTube. This is a free service that lets you upload an .mp3 to YouTube and quickly add a single picture visual, to become a video which is then uploaded to YouTube.
Solid desktop software such as Slideshow Studio HD can also quickly create a simple YouTube friendly video, without you having to load a huge lumbering video editor such as Adobe Premiere Elements. If then uploading the .mp4 manually, ensure you tell YouTube that the video is in English, as otherwise it may later get confused and try to use Spanish etc for the captioning.
3. Once uploaded, then go to YouTube and find your Channel, click the Settings cog on the uploaded video, and turn on “Automatic Subtitling”. If it won’t let you do this, you may need to go into the Dashboard and find the Subtitles tab.
4. Wait a minute or so for the subtitles to be made. Then go to DownSub.com to download and save the video’s subtitles as an .srt standard subtitles file. The Dashboard in YouTube may also let you download a subtitles file without needing this third-party service.
5. Get the Open Source Subtitle Edit 3.5 desktop software. Load the .srt file. In Subtitle Edit: File -> Export -> Plain Text.
6. Load the resulting text into Word, and edit and correct. It’s accurate enough for a ‘speech radio’ type podcast, though without much punctuation and you’ll need to work on it to polish it up.
You can of course get willing hands around the Web to transcribe, but you have to pay them (it’s surprisingly affordable, try Fiverr) and there’s usually at least a 12 hour turnaround time. The above method would help you to meet a much tighter deadline.