To answer your 2nd and 3rd questions...
Once you've got all the SDK stuff set up, you can pretty much plug in your phone, run your project, and Eclipse does the rest. If the phone is plugged in, it loads it up on your G1/ADP1, if not, it loads up in the emulator.
As for the market, you'll have to sign up for a developer account ($25), you'll have to confirm your bank/google checkout connected account (using a small deposit, a-la-paypal/other payment services, assuming you want to sell your apps) and then you'll be able to post your applications to the market. Instead of explaining in boring text how it all works, I took a few screenshots for you.
The main market menu. Lists all your submitted applications, the number of ratings, 'total' rating, total downloads and estimated installations with %, Price, and whether or not it's published. At the bottom right, you'll see the Upload application button...
Upon clicking that, you'll be able to choose the application to upload (signed with non-debug keys, of course,) which language it's localized for, it's title and description, type and category, price...
Whether or not to use copy protection (
supposedly stops non-root users from being able to copy your application,) Which countries you want to release your app or game in, your contact information, and the agreements you've to agree to.
That's about it. Develop your app, sign it for release, upload, and you're done. If you've got anymore questions, feel free to ask
