A regular podcast would be great. Iphone/Ipod touch is hot right now. The current selection of apps isn't great. This seems to be an underserved market to me and a natural space for you to expand into.
You should make an iphone version of Beersmith. This will be a great tool for iphone users and push people toward your full desktop version.
About the only other I listen to is Basic Brewing which leads me to DVD's. Jim has some pretty good DVD's on brewing. There aren't many QUALITY videos out there. If you have the talent, equipment and editing and production skills, a video series at a resonable price would be something to look in to. Of course with all the cheap brewers out there, you would have to compete with all the You Tube videos.
IMO, everything is going or will go web by the time you produced it, so DVDs might be dated? And iPhones don't have a DVD slot yet.
If most of the YouTube content is poorly done, then quality on that "channel" may stand out. Perhaps video there could be the teaser or lead to the full-version audio podcast?
Google has some outstanding 4-minute videos explaining how to use some of their features. BeerSmith could use a handful of those.......how to: set up equipment, set up mash profiles, create recipe, dupe recipe, create a custom report, etc. All the common questions........
As great as BSmith is, people still balk at buying it for $21 if they think a new version is imminent. Do you think of these other products as freebies to drive BS sales, or additional revenue streams? I personally think the better path is free, but with goal of making BSmith the premier software with the best learning tools, hand-holding, quickest learning curve, yada yada. People are just hesitant to pay for stuff. I suppose it's possible you could have a "premium" version or separate key that unlocks all the help videos.