Greek public transportation will get you most places reasonably intact and relatively inexpensively. The Greek intercity bus system used to be described in the KTEL web site (with a slick electronic timetable that occasionally worked) at http://www.ktel.org/. The Karamanlis government allowed that site to be abolished in 2007, replaced by a private company that charges 66 cents per minute for telephone information on routes and schedules -- dial 14-21, English not spoken, and no guarantees. Call ex-transportation minister Michalis Liapis at 210 3614828 and tell him it was a bad idea). But www.ktel.gr at least gives the phone numbers of the provincial bus services in Greek. Or find them below on our page in English. Armed with a map, you have a fighting chance.
There are four KTEL bus stations in Athens, reachable by taxi or city bus. KTEL buses are an adventure, a clean, generally air-conditioned, and often excellent one, though not ideal for tourists, timing-wise.
For Athens city buses and trolleys (0.50 for adults), you can navigate through the OASA web site at http://www.oasa.gr/. With adequate prior knowledge of Athens it is possible using the Greek-language version of the site to find the perfect bus for any situation. The English version is more limited, but still useful.
The Athens Metro system, clean, safe, and pretty self-explanatory, is described by an annoying web site at www.ametro.gr. Tickets are 0.80 and a combined ticket for Metro/bus/trolley costs 1.00. Note that an 0.80 ticket is valid for a continuous journey transferring among all three Metro lines, but a cheaper (0.70) ticket for Line One, the old electric train Piraeus Omonia Kifisia, won't work on lines Two and Three.
Ride the Tram from Syntagma Square to downtown Glyfada or to the Peace and Friendship Stadium (SEF) in Piraeus, to help keep this friendly but slow new system from being killed (0.60).
The Greek train system OSE is slowly upgrading. Trips are cheap but also very slow. For route information and schedules, check their web site at www.ose.gr. Note that the old Peloponnesian train station, 100 meters behind and to the left of the main "Larisa" station but on separate tracks, is defunct. Take the Suburban Railroad (below) to the end of the line, currently Kiato, then switch to OSE trains.
The Suburban Railroad (Proasteiako) has two basic routes as of September 2007: Piraeus-Athens main train station (Stathmos Larisis) to Koropi and the Airport, and Athens to Corinth/Kiato. One transfer point between the two (and to Metro line 1) is Nerantziotissa. The trains are new, comfortable, and accept bicycles. An excellent round-trip day excursion to Corinth costs ten euros and takes about an hour each way. The Corinth station is a 5 euro cab ride from Ancient Corinth or 2 euros to New Corinth. There is a city bus to Corinth from the train station once an hour.
The port of Piraeus is a confusing mess, but daily departure schedules in Greek are available at http://egov.yen.gr/en/yen.chtm?prnbr=30384. Ample info on ferry schedules is available on the GNTO web site at http://www.gnto.gr/pages.php?pageID=49&langID=2
KTEL Provincial Bus Line Telephone Numbers