I have an international flight from Sydney, but the only connecting flight from Brisbane available is the night before. I'm trying to locate a hotel close to the airport for around or under $100 AUS; is there one available?

That wd be about AUD160 at the current exchange rate, and I don't think you'll have a problem with that price range. There's a Hilton and a Holiday Inn out by the airport + some others. Try wotif.com for discounted rates.

What time does your flight leave Sydney Airport?

If it's anytime after about 10am, look for a hotel somewhere more interesting than the airport area. There are plenty of the usual airport hotels, but all are pretty uninspiring, in industrial areas. I think the Ibis offers a $AUS99 deal. The Hilton is not too far away, and the higher rooms may have some views.

Have a look at the Novotel at Brighton, which may be more expensive, but is not far from the airport and right on the beachfront.

Sydney Airport Ibis is good value, under AUD 100
These guys are local with local prices

http://www.freewebs.com/sydney_cheap_hotel_rates/

Yes, Ibis and good. Look at www.accorhotels.com.au for specials

Have fun

I pressume you have checked Virgin Blue for thight also?

It is always a good idea to compare both Virgin Blue and Qantas as sometimes Qantas beats Virgin on price or vice-versa

http://www.virginblue.com.au