What is the difference between Chinese simplified and Chinese traditional?
Simplified is used in mainland China. Traditional is used in other areas, like Hongkong, Macau, Taiwan, etc...
Simplified, no surprise, simplified some (not all) of the characters from traditional.
e.g.
What are some good movies recently?
最近有什麼好看的電影? (Traditional)
最近有什么好看的电影? (Simplified)
That is all, they have same pronunciation, grammar, vocabularies in standard Chinese.
Note: The 'standard' could be argued.
Edited: Some words (not too many) have different pronunciation, but I think that is a topic about dialect or oral Chinese, and has nothing to do with the simplified/traditional characters.