In Reply to: You will need to have posted by Takemetobali on Sunday, 3. April 2011 at 18:49 Bali Time:
If you have a Motorcycle License in your own country, you can go to a motoring organization such as the RAC or NRMA and get an International Driving Permit (IDP). This permit will show that you have a Motorcycle License.
The police in Bali will recognize the IDP as a valid Motorcycle License. In theory, you should also show the police your Motorcycle License from your own country. In practice, I have never been asked to show it.
If you do not have a Motorcycle License from your own country, you will need to apply for a Bali Driving Permit. I have never applied for one, so I do not have any first hand experience of the proceedures involved in getting one. Getting a Bali Driving Permit is covered on this forum and also in guidebooks such as the Lonely Planet Guide to Bali & Lombok.