I am Chinese and I tell you why.
Handwriting is the easiest method to input chinese into ANY electronically (phone, pda, pc etc.), there are no easy way to type chinese, and lots of chinese do not know how to input chinese. There are more then 30 ways or method to input Chinese character, whatever way you use you need a certain level of understanding chinese, I don't see any chinese input method that need not to learn in a proper way, and need months and even years of practice to type it fast.
You may think speech recognition is a good way to input chinese character. Years of developing chinese speech recognition is as long as english but you can see even by now the accuracy is still very low. And believe me, it is much much harder then any other languages to be recognised but computer (I'm not going into details and this will take me a thousands word to explain). Briefly speaking, pronunciation is a nightmare even to Chinese people themselves (there are 200+ dialects in Chinese languages).
Here's a link for some very interesting facts of Mandarin (The official and the simplest, easiest dialect out of the 200+) pronunciation.http://www.pinyin.info/chinese_characters/
Someone may ask Japanese and Korean character input. Japanese has only 50 basic characters and all the characters can be pronounced in English way within 3 English alphabets. All Japanese words or borrowed-from chinese characters (which pronounce differently to chinese) can be formed by the 50 basic characters. Therefore all japanese are able to input japanese characters with a standard english keyboard withount any learning curve. I'm not as familar to Korean as Japanese, to my knowledge it is similar to Japanese, it has very limit amount (less then 50) of basic characters, the way it form characters is more complicate then Japanese, and its a simplier version of Chinese character formation. So it shouldn't be a problem to input Korean character with English keyboards.
Unlike english, all the alphabetes are list on the keyboard or the keypad in mobile phones. Chinese character is being formed in a rather complex structure, there are alphabets -like concept to form Chinese characters but you may need a keyboard with around 700 keys and it will only able to allow you to input not more then 80% of every single chinese characters.
There are straight rules to the order of writing chinese characters, early chinese handwriting recognition softwares still require you to write the character in exact writing orders to recognise properly. As processing power is much fast nowadays and with more sophisticated technologies it is now not a big problem (many Chinese do not know how to write properly).
Back to the main topic, I'm so excited that apple is putting chinese input into iphone and itouch, i have been waiting for this since the first day it announced iphone, and i am always worrying that apple is not paying much attention to the chinese market and therefore not caring to include chinese input. For everyone who are not Chinese and upset about it not supporting handwriting recognition in your language. Believe me, you will never want to use it even it recognise it. The software keyboard is much better. And the handwritting recognition is the only way to ensure all Chinese people who can write chinese (let me repeat...many chinese people don't know how to write chinese) to input chinese character. Foreign people can also have a chance to study and draw the chinese characters to see how much they can do. LOL.
Final words. Depends on the character database built-in, I'm expecting iPhone software 2.0 is not going to able to recognise not more than 3000 chinese characters (out of around 100,000 total characters), but it should account more than 99% of the character in most texts.
Few more links for interesting facts about Chinese characters:http://www.clavisinica.com/character-test.htmlhttp://chineseculture.about.com/libr...blccbasics.htm