Chen Shui-bian has promised not to develop nuclear weapons.

There is some interesting history and law here. The history is that they did have an active nuclear weapons program in the 1970s, but Jimmy Carter shut it down.

The law is that the NNPT applies to nations, and not governments, so a strict reading would say that Taiwan, official name Republic of China, could be considered to have the right to develop and deploy weapons, as it is, according to the UN, China.

On a more pragmatic side, if Taiwan were developing nukes, and China found out, all hell would break loose, though if Taiwan actually had deployed nukes on delivery vehicles before it became known, it would stabilize the situation by forestalling potential PRC invasions.

Generally, I subscribe to the old adage, no nukes is good nukes.