Yeah, this is an interesting development since it seriously diminishes the case for a Symbian version of Pleco - every single e-mail we've gotten about a UIQ version (and I'd say about 80% of the e-mails we've gotten about Symbian support in general) have been for Sony Ericsson phones. Personally I think the P1i form factor would make for a lovely Windows Mobile phone, the screen would be a bit on the small side but the built-in keyboard makes that a bit less important anyway.
If Apple's iPhone SDK proves workable then that will almost certainly be the next mobile platform we support, but if it doesn't, or once the iPhone port is done, we're going to have a tricky decision about what to support next - Symbian still has a massive installed base, but between this and the decidedly-harsh critical reception for S60 Touch I'm not so sure about its future as a high-end smartphone platform, whereas if we were to bite the bullet and do a Java port we could support Android, BlackBerry, *and* put out a weak-but-still-functional Symbian version in one fell swoop.