Apparently the Governors' Club at the Madison Concourse is already nearly (or completely) sold out for the weekend of next year's WisCon (May 24 to 28, 2007), and apparently only half of the hotel's regular rooms are available for that weekend. So if you're going to want to stay at the Concourse for WisCon in 2007, you'd better reserve a room ASAP. Go to the hotel's website to make online reservations (attendee code to get WisCon rate is WISCON31 with no spaces), or call the hotel at 800-356-8293.
(I hesitate to mention this, but I've recently started reserving hotel rooms for such events as early as possible, on the grounds that hotels--unlike airlines--let you cancel reservations at no cost up to a day or two before your intended visit. I definitely don't advocate reserving a room "just in case" you might want to go, because that'll cause problems for other people who definitely want to go but are slower to reserve rooms. But if you're sure you're going, you're just not certain of the exact dates you'll be there, then you may as well make the reservation now; you can always change it later. This is a public service announcement for those who tend to hold off on reservations 'til the last minute because the details of their travel arrangements haven't been settled; I used to do that, and have missed out on good hotel rooms several times as a result.)
Note, btw, that WisCon membership for 2007 is again capped at 1000 people. I'm guessing that won't be as much of an issue as it was in 2006, 'cause there won't be the extra draw of all those past guests of honor; still, it's becoming a popular convention, and if you want to be sure of getting a membership, it can't hurt to go register now.