Hi i Plan to go to Sydney,Austarlia and i Plan to rent a Car would i need a different Drivers's License other than the one i have to drive around Sydney and if so how do i go about getting one thanks for any advice on this!

No.

Hi Danny, I checked this with Hertz for a friend yesterday & I would imagine the same policy applies to all other major car rental firms.

Provided your licence is in English and you've held it for at least 12 months, you don't need an International Licence.

Just remember to keep to the left!
Enjoy your trip.

BTW, in Sydney CBD, you're better off using public transport as parking can be horrendously expensive in car parks & tricky to find where you want it in the streets. I paid $37 for just over 2 hours at Wynyard (railway station, mid-CBD) yesterday

the critical item you need is a valid credit card.

Yes, if you don't have a specific need for a car, i.e. plans to travel outside the Sydney metro area, you're much better off using public transport. The rail network is extensive and extends to nearby cities and buses and ferries will get you just about anywhere else. Despite the fact that I've lived in a number of Sydney suburbs, these days I find driving in the city a pain. If you're not used to driving on the left, multiply that.