All Acts of Parliament start life as Bills, which may be introduced into either the House of Commons, or the House of Lords. General information about Bills is available from the web site of the UK Parliament: http://www.parliament.uk/business/bills-and-legislation/
Full text of Bills currently before Parliament can be found at: http://www.publications.parliament.uk/pa/pabills.htm
Bills from previous sessions can be found at: http://www.parliament.uk/business/bills-and-legislation/current-bills/previous-bills/
Older Bills can be found in the House of Commons Parliamentary Papers database.