Instant booking is available via AIRBNB:
http://www.airbnb.com/h/gallery-house-austin

Note on HOTEL TAXES via Airbnb booking:
Airbnb now collects the 6% State of Texas Hotel Occupancy Tax, and the 11% City of Austin Hotel Occupancy Tax at the time of booking. These are paid to the City and State quarterly.
More information about hotel taxes can be found here:
http://www.austintexas.gov/department/hotel-occupancy-taxes