Patzcuaro is most easily reached by bus or car.
By bus
Several first-class bus lines have infrequent service to Patzcuaro. The Purhepecha bus line a subsidiary of Flecha Amarilla runs very frequent buses between Patzcuaro and the larger cities of Morelia and Uruapan. From Morelia, a Purhepecha bus leaves for Patzcuaro about every 20 minutes between 6AM and 8PM for a fare of 30 pesos August 2009 price. Tip: If your plan is to go directly to Janitzio, get off the bus at the Pemex station when you first come into town --- there will often be several people getting down there. The boat dock is a few short blocks walk.
By car
Patzcuaro is an easy drive from the Pacific coast towns of Ixtapa, a resort community, and former fishing village Zihuatenejo, which has a large airport. Visitors may take a modern toll road about $8 in tolls for a four hour drive or the essentially parallel "libre" road, which winds through beautiful country; turn north northwest of Ixtapa and follow road signs to Morelia. Don't forget that in Mexico, a left hand signal from the car in front of you [generally] means it is safe to pass.
You can also arrive from Guadalajara via the Guadalajara-Morelia-México toll Highway: exit at Coeneo Huaniqueo Coeneo direction, after Coeneo, head to Quiroga, then to Tzinzunzan and finally to Pátzcuaro. Foreigners should be warned that highway signs are sometimes scarce and not very well placed. People are usually helpful if you are lost, but you have to know some basic Spanish.
A Michoacán PDF highway map is available from the Communications and Transport Secretariat website (http://dgp.sct.gob.mx/fil...) maps for the other states can be found at the same site here: (http://dgp.sct.gob.mx/index.php?id=440).