Correct. I have to build Capsuleer against the OS 3.0 libraries to make use of any of the features. This will remove its ability to run on a 2.2.1 device.
Ah, ok. I wasn't sure what the development/publishing environment was like on the phone. That's straightforward enough.
I'm first-gen iphone (unlocked, jailbroken, and I understand you can't consider that); my opinion is that if the only 3.0 feature you'd really use is push notification to warn people of skill training then it's probably not worth alienating < 3.0 itouch users. (How would that look, btw? Would you push out a badge number indicating the number of skills in the queue? The number of hours until the queue is empty? Days? Something obvious that I'm missing?)
I'd certainly love the feature myself, though. :-)
Does Apple supply developers with general userbase information? Like: Will they give you numbers down the road so that you know roughly how many people pay to move to 3.0, so you can gauge what percentage of users you might be leaving behind?