I hate to say this, but I have installed Nitdroid and gotten it working about five times, and deleted it every time. It just doesn't seem ready or anywhere near it, and I am becoming increasingly dubious about Android as a result. I mean, no multitasking seems to be a pretty big deal to me.
I'll still give it more chances. I hope I'm wrong. But I am quite happy with the N900 without Nitdroid and have been for quite awhile.