1) You register online. The price they currently show is the early registration deal. Last year that expired at the end of April. Even though you register online, you have to pick up your badge at the site. I recommend not waiting until Monday morning. Head over on Sunday afternoon.
2) All sessions are open to all attendees. I didn't see anyone turned away from a session last year, but some were definitely full rooms.
3) If I am remembering correctly, the day starts at 9:00 and ends at 6:00 except for the first day when the keynote starts at 10:00. Be there no later than 7:00 on the first day if you want to be seated in the main hall for the keynote. Lunch break is 90 minutes. Apple provides lunch. Again, going from memory. Sessions are an hour and 15 minutes long with 15 minutes between sessions.
4) There are three kinds of badges. Apple employee, student, and everyone else. The Apple guys are held back and only get into sessions if there is room. The students have access to special sessions (meetings with companies that are hiring), but got screwed out of being in the main hall for the keynote last year. The rest of us (Premier, Select, and on-line) all have the same badge.
At some point Apple will probably be posting the session schedule. It is definitely a work in progress. They will post a few sessions and then add some and then move some and then add some . . . This goes on right up through WWDC. It's not chaos. Apple does a good job of organizing it. I'm just letting you know what to expect.
If you are flying in for this, don't worry about transportation. The local train (BART) will take you from the airport to the convention center for $5.15. I recommend getting a hotel in the convention center area. It will probably cost you $200-$250/night.