Accommodation in the major ski resorts is plentiful, ranging from backpacker to luxury houses and chalets, although given the length of the ski season (only 4 months), can be quite expensive. For those wanting to ski at Thredbo or Perisher, Jindabyne offers a great range of (generally cheaper) accommodation options, catering for families to couples and large groups.
On snow accommodation (ski in, ski out) is offered in all of the major resorts, however it is generally much more expensive than accommodation off mountain. Thredbo, Mt Hotham, Mt Buller and Falls Creek all have a European alpine village feel, with on snow accommodation surrounding the mail street shops and restaurants. Perisher has less of a village feel to it, and has been trying to obtain rights to redevelop the accommodation and village at the base of the mountain, however this has yet to be approved by the NSW government.
If you are prepared to rough it, then there is a camp ground in Jindabyne with camp sites, powered sites and cabins (Discovery Holiday Park – http://www.discoveryholidayparks.com.au/nsw/snowy_mountains/jindabyne) and one in Saw Pit Creek (Kosciusko Mountain Retreat – http://www.kositreat.com.au/) located just inside the Kosciusko National Park, approximately 15-20 minutes drive from the ski fields.
There are a number of websites (ski.com.au, lastminute.com.au and gostay.com.au etc) and operators that offer online accommodation bookings, however you may find it less expensive and less time consuming to purchase an all inclusive ski resort package (including travel, accommodation, lift passes, ski hire etc) than booking accommodation separately.