I am sorry you didn't get any earlier responses to your post sugarlumpkin, I think the Australian/New Zealand tribe is a small one.
Not sure what your sister in law is into but here are some ideas:
(Prices are in Aussie dollars $A)
General tourist website for NSW:http://www.visitnsw.comSydney City Searchhttp://sydney.citysearch.com.auSydney Towerhttp://www.sydneytower.com.au
Admission: Adult $25.00
Sydney Observatoryhttp://www.sydneyobservatory.com.au
Admission: Adult $10.00
State Library of New South Waleshttp://www.sl.nsw.gov.auSt Mary's Cathedralhttp://www.stmaryscathedral.org.auThe Australian Museumhttp://australianmuseum.net.au
Admission: Adult: $12
The Powerhouse Museumhttp://www.powerhousemuseum.com
Admission: Adult $10.00
Art Gallery of New South Waleshttp://www.artgallery.nsw.gov.au
Admission: Free
Museum of Contemporary Arthttp://www.mca.com.au
Admission: Free
Hyde Park Barrackshttp://www.hht.net.au/museums/hyde_park_barracks_museum
Admission: Adult $10
Fox Studios - Moore Parkhttp://www.foxstudiosaustralia.comSydney Opera Househttp://www.sydneyoperahouse.comWalk across the Sydney Harbour Bridge
You can walk across the road level path for free but it will cost money if they want to climb the bridge
http://www.bridgeclimb.comThe Sydney Conservatorium of Musichttp://www.music.usyd.edu.auRoyal Botanic Gardenshttp://www.rbgsyd.nsw.gov.au
Admission: Free
Luna Park - amusement parkhttp://www.lunaparksydney.com
Admission: Free but you have to pay for the games and rides
Tour the Sydney Football Stadium and Sydney Cricket Groundhttp://www.scgt.nsw.gov.au/Tours.html
Admission: Adult $25
Bondi to Bronte Coast Walkhttp://www.waverley.nsw.gov.au/counc.../coastwalk.asp
Admission: Free
Visit The Rockshttp://www.therocks.comVisit Darling Harbourwww.darlingharbour.com.auAustralian National Maritime Museumhttp://www.anmm.gov.au/site/page.cfm
Admission: Entry is free to the museum's core exhibitions
Chinese Garden of Friendshiphttp://www.darlingharbour.com/sydney...ese_Garden.htm
Admission: Adults $6
Sydney Aquariumhttp://www.sydneyaquarium.com.au/default.asp
Admission: $31.95
Sydney Wildlife Worldhttp://www.sydneywildlifeworld.com.au/home.aspx
Admission: Adult $31.95
Taronga Park Zoohttp://taronga.org.au
Admission: Adults $41.00
Centennial Parkhttp://www.centennialparklands.com.au
Admission: Free
Royal National Parkhttp://www.environment.nsw.gov.au/Na....aspx?id=N0030Explore the shops at Newtownhttp://www.visitnsw.com/area/Newtown.aspx
Admission: Free (unless you buy something at the shops)
See a gig at the Enmore Theatrehttp://www.enmoretheatre.com.auShopping:
Places to shop in the city:
http://cityofsydney.nsw.gov.au/sydne...e/default.html
Shopping Malls:
Westfield Shopping Centreshttp://westfield.com.au/aucentresSydney Ferries:http://www.sydneyferries.info/
You can jump on a ferry and either do a rond trip and see the Sydney Harbour or you can visit some of Sydney's islands:
Cockatoo Islandhttp://www.cockatooisland.gov.au/about/index.htmlThe Quarantine Stationhttp://qstation.com.auFort Denisonhttp://www.cityofsydney.nsw.gov.au/A...ortDenison.asp
* Take a walk around Circular Quay and the Sydney Harbour foreshore
* A picnic in one of the parks by the beach (Clovelly, Coogee, Bondi, Bronte)
* Take A walk around Watsons Bay and eat fish and chips from Doyles (the takeawy part not the restaurant)
There is a show called Sydney Weekender (chanel 7, 5.30pm, Saturday) dedicated to what's things to do in Sydney.
http://www.visitnsw.com/Sydney_Weekender_p1488.aspx
If they get sick of Sydney they can take a cheap flight to Melbourne, Canberra or Brisbane:
http://www.jetstar.com/au/en/index.aspx or
http://www.virginblue.com.au
