General 

There are a range of taxi companies in Sydney, all with different paint jobs.. They all have an identifying light on the top of the cab which indicates whether the taxi is available for hire.

To hail a taxi, you simply use your arm to flag them over.  If they're for hire they'll be on the look out, and you should hardly have to twitch for them to realise you're in need of a ride, though by all means jump around in a most exhibitionist fashion if that gives you pleasure.

In Sydney CBD, Elizabeth St or George St are both good for hailing a taxi. You can save some money by having a reasonable idea where you're heading, and hailing from the appropriate side of the street, it can add quite a bit to your fare if the taxi has to go in a circle around the city to head in the direction you want.

You will find useful information about travel by taxi in NSW on the NSW Ministry of Transport website. The site includes: how to register lost property; what you should be charged; a guide for passengers and a facility for feedback. 

Disabled transport taxi operators. 

The NSW Department of Transport website also provides information about wheelchair accessible taxi hire.

Taxi operators

There is a list of Sydney taxi operators on the NSW Ministry of Transport Website.  Use the wheelchair accessible taxi link above.