The simplified script is used in Singapore and Malaysia as well, and possibly in other countries that wish to be on good terms with the PRC.
It is interesting to note that one of the biggest headaches caused by Taiwan not adopting the simplified form (or mainland China doing the opposite) arises when one wishes to type something in Chinese on a computer.
In countries where the simplified script is used, the character encoding format of choice is known as GB, while in Taiwan, the BIG5 format is used. As is the way of most things between China and Taiwan, the formats are incompatible; a system that can only understand GB will be unable to read a document in BIG5, even though the two character sets should have a one-to-one correspondence.
As a result, most people use BIG5 to GB converters in order to translate texts, a hassle which could be easily avoided if a single standardised encoding system was used, with different typefaces to allow for either simplified or traditional view.
Of course, there may be some technical difficulties in implementing this that I do not know of.
But in any case, Unicode will probably solve all the aforementioned problems.