Advice for an Aussie Working Holiday maker
Regarding short term accommodation, I can recommend the following youth hostel in Sapporo
I recommend you visit the Sapporo International Communication Plaza as soon as you get there.
They have lots of information. You can meet Japanese people there and maybe find out about homestays or work. The Plaza offers an free English conversation service where Japanese people can come to the office and talk with native English speakers, so dont be surprised if people come up to you and talk to you. The staff are very friendly. And its free.
It may be worth calling into the Australian Consulate office in Sapporo and introducing yourself and explain your plans. They can sometimes provide you with contact information of people who can help.
http://www.business.australia.or.jp/sapporo/english/ You need to make an appointment. I think the head of the office is a nice Australian lady called Joanna Nursry-Bray
One of our contacts in Nisseko is Scott Walker. He is a good friend of my wife's family. I am sure that if you called Scott and mentioned that Tetsuko Nichols (previously Tetsuko Kadosaki) suggested it may be worth saying hello, he may be able to give you some good advice. His contact details can be found on this website at http://www.outdoorjapan.com/gear-services/outdoorad-sas.html
If you are looking for a job teaching English, most of the schools will take you without ESL qualifications, but it doesnt hurt to have it. You can also teach freelance. Teaching English is not the best environment if learning Japanese is a priority.
I hope this advice helps and you enjoy your stay. Internet cafes in Japan are called Mangakissa (literally a comic cafe). They are a bit different from Australia. You can choose a booth where you can watch videos, TV or use the Internet. Many of them operate 24hours and the reasonable price includes drink all you like tea, coffee or softdrinks. Some of them have showers as some people stay late, fall asleep in their booth, wake in the morning and head off to work etc. This makes for really cheap accommodation with entertainment thrown in. If you are going to do that, the trick is to find a non-smoking one (they are rare but increasing) and also request a room with a mat rather than a chair as it is better for sleeping. There is one cafe I used to use diagonally opposite Starbucks and across the road from Mitsukoshi Department Store near Odori Park. It is on the 2nd or 3rd floor. Although it is not non smoking, I heard they have another store closer to the Sapporo Station which is non smoking.
A couple of other things to keep in mind are : you will learn more Japanese and more about Japan if you stay with a homestay. If you plan to travel around Japan, a Japan Rail Pass which you can only buy outside Japan is a good investment. One cheap and alternative way to get to Tokyo from Hokkaido is by ferry from Tomakomae. About 7500yen for the lowest class (sleeping in a large room with Japanese truckies). You have to add to the cost the Bus from Sapporo Station, the Bus from Oarai to Mito Station and the train from Mito to Tokyo, but it still works out cheaper than the train or plane from Sapporo and as it travels overnight, you can cut the cost of one night stay.