Two companies are now offering bus tours of the city. One is a local company, Tranvías Turísticos (no phone), which offers two tours on small buses that look like trolley cars. Get info and buy tickets from the kiosk in Plaza Guadalajara (in front of the cathedral) from 10am until 7pm. There are two routes. One is a circuit through downtown and surrounding neighborhoods. It lasts 1 hour and 10 minutes. The second is a slightly longer tour, going to Tlaquepaque. It lasts 1 1/2 hours. Both cost 90 pesos.
The other company, Tapatío Tours (tel. 33/3613-0887; www.tapatiotour.com), has modern, bright-red double-decker buses. Its tour goes from downtown to western Guadalajara to Tlaquepaque. The tour costs 100 pesos on weekdays and 120 pesos on weekends. It goes farther out, into western Guadalajara. There are 10 stops; you can get off at any one and catch the next bus when it passes by, which is every 45 minutes to an hour. Catch the bus in the plaza on the north side of the cathedral after 10am.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.