&#183 There are many so called "apartment hotels" in Tokyo. Have a look at the English language publication Japan Yellow Pages, which lists them. It should be available from large bookstores or in a Japan government office.
Richard S

&#183 You're best bet would be to stay in a "gaijin" (foreigner) guest house. You rent your own private room and share toilet and kitchen facilties. They can be rented by the week or month & tend to have a mixture of short and long-term residents who like the convenience that this brings.

The deposit is usually about 10,000 yen or 50 pounds and rents run from about 45,000 yen (250 pounds) to 70,000yen (380 pounds) per month. They are usually centrally located (wouldn't be much use if they weren't) and the rent includes all bills with a payphone in the hall. Check out the classified adverts at www.tokyoclassified.com. I'd recommend them & I'm moving into one this weekend due to crippling apartment costs.
ganbatte!
Peter Collett