Because the stylus became a dirty word, pen-based note taking really hasn't taken off. That's a real shame because lots of folks want to take handwritten notes or draw diagrams and charts. For better or worse, Evernote is the best solution right now, and on the HTC Jetstream and Flyer actually works extremely well with the pen since they designed the tablet with Evernote integration in mind. There are free and pay for versions of Evernote, and even the free version replicates a surprising number of top features in OneNote. Evernote is not an HP product, BTW.
If you use remote desktop access, the pen is interpreted as a mouse, so it won't get you a virtual One Note experience unfortunately.
There is a free Evernote to OneNote converter here: http://www.mobilenoter.com/Evernote . I haven't tried it, but it can't hurt to try since it's free.