not avail to new customers

Paul's right - 'yes' Weekend per se isn't offered to new customers anymore,
but if 10-minute weekend calls to mobiles is your specific primary need,
there are some (very) similar options, including:

Telstra 20c for 10 min Weekend bonus option
-20c for the first 10 minutes to Australian terrestrial mobiles
-8pm Friday to midnight Sunday
-pretty much the same offer as 'yes' Weekend, with 4 extra hours on Friday
-only available on fixed-term contracts - minimum 12 months
http://www.telstra.com.au/mobile/mobiles/prices/plans.htm#2

Optus 'yes' talk option
-30c for the first 10 minutes to Australian terrestrial mobiles
-8pm-7am weekdays, plus midnight Friday to midnight Sunday
-10c more per call than 'yes' Weekend, but you get the benefit of using at
night too
http://www.optus.com.au/yesplans