I'm quite a fan of random posts around the city and there are plenty of them. And U-park have some free bike parking around. But I don't know about the rest. I think this might be a job for...*drumroll*...http://www.openstreetmap.org/
Good question! The Govt's TravelSmart guide for the city includes showing where you can hire bikes in the CBD, where there's bike lockers (at the railway), and also where you can hire bikes. But not detailed parking unf.
The TravelSmart guides in general are quite good, worth collecting the whole set as they fold up small and easy to tote around when cycling.
OpenStreetMap? Interesting. THere is also the http://www.walkscore.com/ project, who are thinking about adding cycling features.