From the official site:
WordCamp is a conference that focuses on everything WordPress. WordCamps are informal, community-organized events that are put together by WordPress users like you. Everyone from casual users to core developers participate, share ideas, and get to know each other. WordCamps are open to WordPress.com and WordPress.org users alike.
The 2012 Milwaukee WordCamp will be held at Bucketworks on 706 S 5th St, Milwaukee, WI 53204 on June 2-3, 2012.
Visit the official website for more details and tickets.