You are right, the typical podcast is around 20 MBytes. Depending on the quality, they are often around 500Kbytes - 2MBytes per minute. Maybe you are misreading the size. 16 minutes might be 10 Megabytes (or 10000 KBytes).
Greg Smith
Author, FeederReader - Pocket PC *direct* RSS text, audio, video, podcasts
www.FeederReader.com - Download on the Road