Works comes with a lot of computers becuase it is cheaper than the full Office, it has the full blown Word, and then another program with some other cut down versions of office programs.
A lot of laptops would come with the Student and Teacher edition of office, which is Excel, Word, PowerPoint and Outlook.
Basically, you don't find many PCs without an Office app of some sort, really cheap ones would have OpenOffice(or nothing), most mid range ones would have Works or Office Basic/Student and Teacher, and higher end ones or business ones would have the full Office suite.
It's also cheaper to buy office and works with your PC, works is about AU$80 with a new PC.