Hi Alan,
The six records are 3 for Tickets of Leave and 3 for Ticket of Leave Passports.
A
ticket of leave allowed convicts to work for themselves on condition that they remained in a specified area, reported regularly to local authorities and if at all possible, attend divine worship every Sunday.
Ticket of leave passports allowed convicts holding tickets of leave to travel between certain points, visit a certain place or to attend the city markets for a specified period of time.
I believe all are for the John who was tried at Wiltshire, except the last ticket of leave which was for the John tried at Norfolk.
The year column is the year of the ship's arrival (essential for them to keep track of all the John SMITHs!!)
The date column is the date the ticket of leave/passport was issued to the convict.
The "No" column is the reference number of the ticket and always consists of two numbers - the last two digits of the year it was issued, and the actual ticket number. For example 36/041 is a ticket issued in 1836, and the ticket number is 041.
As you can imagine, with thousands of convicts, many with the same name, there had to be a system for keeping track of everyone. You will find that your convict was always recorded with their year of arrival, ship name, and often trial date and place. Many of the ships made multiple trips to Australia, and there were many different ships with the same name. When this happens you will see a ship named as, for example, Mary Ann I (3), which is the first vessel named Mary Ann on it's third voyage. I don't know how the convict administrators managed all this without loads of coffee and Panadol - rum maybe?

Convict records, including tickets of leave are free to search on Ancestry until 31 January
http://www.ancestry.com.au/The 1841 census for NSW only records heads of households by name (which is why there are only a few women), and only provide age span, sex, free or convict status for others in the household. As both Johns were still convicts they would not be recorded by name.
http://www.rootschat.com/links/0bit/ They do both appear on the 1828 census, one at Hyde Park Barracks in Sydney, and the other is assigned to Charles WHALEN at Prospect. A bit of trivia - it was this Charles WHALEN's two sons who were the first Europeans to find and enter the Jenolan Caves. (apart from possibly a few bushrangers)
Just taking a couple of sentences from JM's post and adding to them:
The John Smith whose ticket of leave places him at Carcoar (NSW) was tried at Norfolk Quarter Sessions.Tried: 12 or 20 July 1825 Norwich Quarter sessions (Life)
1853 Recommended for a Conditional Pardon
The John Smith whose ticket of leave places him at Liverpool and Paterson (NSW) was tried at Wiltshire Assizes. Tried: 16 July 1825 Wiltshire Assizes - Robbery (Life)
Native Place: Salisbury, Wiltshire
Born: 1808
1 July 1842 Conditional Pardon
The microfiche indexes for NSW give baptism area codes (I don't know why they didn't bother to put them online) and I will check this out for you tomorrow - not sure if it will help though. It is very difficult to trace anyone forward in time (which is why we go backwards), let alone someone named SMITH!
Debra