Sorry if this seems to have a painfully obvious answer, it probably does, but I can't find it. What steps do I take in order to upgrade my version of Podtrapper on my BB?
No, not obvious. It doesn't actually tell you anywhere, but PodTrapper is always checking for new releases. If any are available it will let you know and allow you to upgrade in-app. There are beta releases you can try, though, if you're interested.