Stephenie Meyer has blogged on her myspace regarding The Host tour:

Just a reminder that many of the events on The Host tour still have tickets available. I’ve seen a few comments from people looking forward to the Breaking Dawn tour, so I wanted to reiterate that The Host tour is the last big tour that I will be doing. Chances are that if I’m coming somewhere close to you, I won’t be coming to the same city the next time around. Also, there won’t be as many events on the Breaking Dawn tour, which means not as many tickets. At most of The Host events, I will be able to sign a couple of your Twilight Saga books, so if that is your goal, don’t procrastinate.

All the information about the events on my The Host tour and the rules for the individual events are up on my site’s calendar page.