I'll try some quick answers based on what I've seen myself.

1. Application styles. Actually there are many styles today (Sidebar gadgets, HTAs, Console vs. Windows subsystems, Services, etc.) but with Win8 we get a new one: Metro style. Metro emphasizes touch input, async operations, flow-based layout (HTML or XAML), etc.

2. Metro distribution. Mostly via an online Microsoft store.

3. Metro distribution requirements. Yes, code signing, paid testing process, paid membership in the online store, Microsoft takes a cut of each sale - possibly as much as 30%.

4. Yes the "Start" button takes you back from eskto to the Metro Launch/Start screen instead of a Start menu. Start Menu can be re-enabled (disabling Metro), but this seems to break some things making it impractical to run this way - at least in the Dev Preview.

5. Traditional Windows programs are supported.

6. ARM. Yes it appears ARM Win8 can run Metro programs compiled for ARM, Windows programs compiled for ARM. There is no "Windows on Mac" and never was. But "Mac" moved to Windows hardware a while back and Windows can be installed on these boxes just as Linux, etc. can.

7. VB6 runtime is in Win8 DP. I haven't tried the IDE myself.

8. No, Win8 can use a regular BIOS. On hardware with the new-style BIOS-replacement firmware the hardware maker can enable or require signed-code boot loaders.

9. Installing Win8 DP "on the metal" (not in a VM) is just like installing it on any machine. I believe it tweaks a few BIOS settings to help make booting appear to go faster but this is unproven.