The city has a nice website with water saving tips and other info, plus the rebate application for several city run programs. I've taken advantage of several: a free toilet and rebates on my rain barrel and my fancy new front loading washer. The toilet rebate is awesome- my old stinky toilet was replaced with the toilet of my choice, a lovely high efficiency model. I also love my front loading washer and i would have gotten my rain barrel anyway, but didn't mind the rebate at all. As far as i can tell this native planting rebate is brand spanking new and very worth looking into. For more information visit this page.
Basically, the city will pay you money per square foot of land that is turf converted to native plants. You get more money if the turf was irrigated than if not and you have to convert at least 500 square feet. Very cool program.
Water Wise Austin . org is the place to go for all kinds of water saving tips and applications for several rebates you may not have known about. Check it out!