Bloomington Transit runs an extensive network of buses through the city. The central station is located downtown at 3rd and Walnut, a 15-minute walk from the IMU and 2 blocks from the Monroe County Convention Center. For a map of routes, see this PDF.
If you're coming from out of town, Bloomington is roughly 45 minutes south of Indianapolis, two hours from Louisville, and four hours from Chicago. At the Ground Transportation Center of the Indianapolis International Airport, located on Level 1 of the Parking Garage, you can claim rental cars or catch a taxi, limousine, or shuttle to Bloomington. The Bloomington Shuttle service provides transportation between the airport and the IMU, the Courtyard by Marriott, the Hilton Garden Inn and the Hyatt Place Bloomington for $20 per trip online or at stop kiosks (online reservsations suggested to guarantee spot).
If you plan to drive or rent a car, free parking is available at the Courtyard by Marriottt next to the Bloomington Convention Center. You can find information about on-campus visitor parking from the Office of Parking Operations. Garage parking can cost up to $24 a day, and the IMU pay lots cap at $20 (parking is free for customers of the Biddle Hotel). You can also find lots and garages operated by the City of Bloomington downtown (see a list of rates).