FlyInside XP (there are two editions, and if you own FlyInside FSX/P3D you don't own FlyInside XP sadly) works well. It's best at the moment for VFR flights, as some of the X-Plane native 'pop up' windows you need for IFR (FMS, Map, ATC maybe) don't work as yet. The FI author is planning an update to fix that in April, so hopefully not long. As I've packed my TrackIR away, I really only use XP11 with FlyInside and VR now. It has it's own type of ASW so it makes for a smooth 90 fps, even in XP.
Austin has said they are working on native VR support, but not sure for when. My best guess it will be more than 6 months (about 2 months ago) so it was worth it to use FlyInside till then. The author of FlyInside did some clever stuff with frame rates and custom interpolation, and I have my doubts the native VR support will be as good (given X-Planes track record on frame rates being important ) .
FlyInside has a 15 minutes fully functional demo flight time limit, which lets you get a really good idea of how well it'll work on your system and how well it works - if you try it you'll probably buy it though