Our next project after iPhone is our desktop companion software, because we've been putting that off for way too long and some of the painstakingly-negotiated licenses for it may expire if we don't get on top of it soon. (not to mention the number of people we've kept waiting)
After that, though, I'm not sure whether we'd do an Android or a web-based version; assuming we can get the licenses together (which looks pretty promising), there's a strong case for the latter, since in addition to supporting Android it would also let us do something for BlackBerry users, who I tend to think are considerably less likely to consider an iPhone / Windows Mobile / webOS phone than Android users, since a lot of them are locked into BlackBerry by their employers. And of course we'd also get to support Symbian, Maemo, weird-proprietary-Samsung-OS, etc. The business case for offline software grows weaker with each passing year, and Android even with its new native code support looks to be a very difficult platform to port to; the small number of people who really need to be able to use Pleco on airplanes / in the middle of nowhere where there's no cell coverage / etc would still have iPhone, WM, and webOS to choose from.
Also, of course, we need to get cracking on new versions of our existing software, since there are a lot of new features in the queue for that - component-based character searches, all sorts of flashcard improvements, sandhi-sensitive audio, better custom dictionary indexing, online dictionary update submission, built-in support for getting a new keyfile / downloading add-ons, etc. Not to mention a couple of categories of dictionary we'd very much like to secure licenses for. We can't put all of our efforts into platform support at the expense of new features.