Somewhat like Spanish, which has two "to be"-esque verbs (ser and estar), Japanese has two basic "to be"s:
desu (です) and arimasu (あります ). In Spanish, ser is for things of permenance (Soy americano, soy de Atlanta, pero vivo en Norcross y estoy un poco cansado .. es hace caliente en nuestra oficina) and estar for transient states. In Japanese there are (at least) desu for "is equal to" and a seperate verb arimasu for "is located". Perhaps even more interesting is that arimasu is reserved for inanimate objects, and for people another form imasu ( います) is used.
The negative forms in Japanese are pretty straighforward, and I have about absorbed the principle which explains the "A ja nai desu" common in Irasshai2 and used in Japanese for Everybody3. Past tense, and the wonderfully useful uncertain tense are done with suffixes.
1:ISBN: 1-4000-2019-0 is a small book and CDs set for $25 USD