Here is a useful website – ‘Type in Chinese Online‘ (It’s free) where you can type Mandarin text right in your browser without installing software such as NJStar or Google PinYin (the best Chinese Word Processor).
The website is useful in situation where you don’t have the authority to install software into the computer, like in your office or cyber cafes. It is the only way to type Chinese text online, another indirect alternative in typing Chinese text online is by translating it. Not quite the same but the end result is still the same, Google translator has the ability to perform this simple task, just type in the English word and hit the translate button – Volla!
The above translating method can be quite troublesome due to the different structure and grammar of English and Mandarin, as for those that has the luxury of installing programs into their own computer, I highly recommend Google PinYin, it is the best and perhaps the most intelligent Chinese word processor ever. Intelligent as in it can predict the next Chinese character while you are about to typing. Google Pinyin IME (谷歌拼音输入法) is an input method developed by Google China Labs. Simply amazing, do read more about Google PinYin in Wikipedia.