if you ride into the city on the Keisei Skyliner, this service terminates at "Keisei Ueno", which is a separate building about 1/4 mile from the main Ueno station. The Tokyo municipal tourist bureau operates a really nice information counter there; there are at least two decent sized guides on glossy paper that you can get in English that have detailed city maps of central Tokyo, including information on the two different subway companies (Tokyo Metro and Toei Subway) as well as the above-ground trains such as the Yamanote line. The Keisei Ueno station offers a covered connection to the Tokyo Metro (it is about a 1/4 mile walk to the actual subway platform on the Ginza line).

The ticketing machines in all the stations have a feature so that upon pushing a button on the screen the read out will be in English. You can buy an all day pass good for both subway companies for something like Y1000. You can also buy a JR Tokunai pass good on all JR rail lines operating within the 23 boroughs of Tokyo for Y730.