You're not following the order of the books in the bible; why not?
The texts of the bible have been put collected together in many ways throughout history, and those collections have ordered and organized the texts in different ways. In Hebrew collections of the Old Testament books, Ruth and Esther are placed alongside Psalms and Proverbs as part of “The Writings” at the end of the collection. In the King James translations, those same books are included in “The History”, and placed earlier in the collection.
A similar reordering of the New Testament texts when you compare the King James translation with the Slavonic Bible, or with the Luther Bible. Each collection takes liberties with how it orders and organizes the biblical texts.
So, in answer to the original question, the reason The Bible Podcast doesn't follow the order of the books in the bible is because there is no “order of the books”. They were written separately, collected separately, and organized differently by the people and groups who collected them together. I have felt the freedom to continue in that tradition, and to organize this collection of biblical readings in a way that seemed appropriate to the purposes of the collection.
In the beginning of the podcast, I chose to read John and Romans, because I believe that these two texts, taken together, serve as the best introduction to the nature and work of Christ. Now, I choose books with an eye toward balancing history and theology, narrative and rhetoric, Old and New Testament. It's not very scientific, and it relies heavily on my own whim and fancy.
Once the project is finished, you can feel free to come back and listen to them in whichever order you like.