sfrrr - the iPhone app supports all of the dictionaries from Palm/WM except for Oxford, which we likely won't even be selling anymore on Palm/WM as of this summer (though you'll still be able to use it if you already bought it) and which would not be any more likely to show up on some other new platform like Android than it would on iPhone.
Handwriting on iPhone is delightful IMHO - demo video at
http://www.youtube.com/watch?v=gZTbCME4jZA (or
http://www.plecomirror.com/ipdemovid.html for people reading this who can't access YouTube) will show you how that and other things work, the multitouch bit alone is worth the switch. Highlighting words in email and looking them up in Pleco isn't even well supported in Windows Mobile 6.5, but it's not technically possible for an app to do that on iPhone, or AFAIK on Android (or webOS, or anything else) at the moment. However, you can copy a block of text from an email to the pasteboard, open up Pleco and bring it up in the document reader.
And you definitely should do some research on jailbreak apps - all sorts of lovely features like multitasking / new app launchers / native VOIP / etc can be made possible by jailbreaking, so that should help considerably in making you comfortable on iPhone.
mfcb - fair enough, by the time those phones break we may have started supporting another new mobile platform that you like better. (or offering a web-based dictionary, which would work on basically whatever smartphone you feel like using) And technically WM6.5 is still going to be around for a while, it's just not likely to get a lot of people excited anymore (see
http://gizmodo.com/5472100/the-spectacular-maiming-of-windows-phone-65x).
Sarevok - understood; I've gotten a lot of anti-Apple mail since we started supporting iPhone, actually. But when we started supporting WM I got a lot of anti-Microsoft mail, and personally while I admire their technical proficiency there are a whole bunch of reasons why I can't stand Google - unless you're working with an innocuous little company like Palm you're always going to alienate some people.
goulniky - maybe, but the HD2 is sort of a weird hybrid (capacitive screen isn't ideal for text selection or handwriting input), and WM6.5 in general doesn't run Pleco quite as well in some respects as earlier versions (see my response above to sfrrr on Instant Access), so you might actually be happier sticking with a WM6.1 device.
The real question, assuming WM as we know it is in fact dead, is where do we go next - I stand by my earlier comment that at least initially we'll probably just work on polishing / refining things on iPhone (and probably also doing some work on desktops), but it seems like after that there won't really be any other C-based platforms we can develop for, so the question is whether we rewrite our code base in Java (for native Android / BlackBerry / Kindle apps) or build it into a website (which could actually keep using C for the low-level stuff, at least initially; if it runs on our server we can write it in whatever language we want).
Personally I'm inclined towards the website option - the inconvenience of requiring a network connection notwithstanding, I'd really like to be able to get out of this constant cycle of chasing after new platforms and focus on just building one really great product that runs everywhere. Even a flashcard-less Java / Android port wouldn't be out before the end of 2010 (absent a large infusion of capital / programming talent), and wouldn't be flashcard-equipped / refined / fully de-glitchified until mid-2011, and by then 4G cell networks / spectrum reallocation / WiFi-equipping of airplanes may be well on their way to making web-based mobile software comparable to native software availability-wise.
Plus I'm still worried about Android for a lot of reasons, potential incompatibility / market fragmentation chief among them (c.f. the articles circulating today about cell carriers banding together to make their own app store) - we're just a couple of greedy telco executive decisions away from Android development turning into J2ME development, i.e. rewrite-your-software-for-every-phone-model-you-want-to-run-on and vet it through 9 different carrier-specific application stores.
