First to say i don't have any affiliation with these mobs - its actually probably about 6 years since i went to this one but as per the site it does have some princessiness about it - and does some very nice reds too -
http://www.goonawarra.com.au/venue.html
I'm pretty sure a friend of mine was planning to have his wedding here -
http://plunkett.com.au/About/aboutcentre.html at one stage - he has pretty good taste in these things so it might be worth a look
finally and further away - but probably my pick were i to be getting married anytime soon would be -
http://www.tahbilk.com.au - aside from teh fact that i drink my bodyweight in their products pretty regularly they have a really great [but cheapish] cafe right out over the river [if michelton's restaurant is open they are worth a thought as well] i can't find a good pic of tahbilk but trust me it is a very pretty place to be and you can encourage your friends to buy you Magnums of the 1860-vine shiraz as wedding presents [i was lucky enough to get one of these that i might crack for my 25th wedding anniversary]
hope this is of some assistance in a vaguely northerly direction - i strongly advocate visiting all venues in person [and any other venues you can find] you test the wines and the fiance can check for shrubs on which her dress might snag or whatever it is that princesses have to worry about