Revenue have published Guidance on the new parking levy which was introduced in F(No.2)A08. While clear and helpful, it doesn't tell us anything we don't already know. There are no details of the areas affected, nor of the start date.
The start date for the levy will be determined by the Minister for Finance and will be included in an Order to be made by the Minister. Similarly the affected areas will be subject to Ministerial Order - "The specific areas in which the levy will apply will be designated by Order(s) of the Minister for Finance following consultation with the 5 city councils." That's the Councils of Cork, Dublin, Galway, Limerick and Waterford.
If you are employed in these cities, it's conceivable that you are already incurring a liability to tax by virtue of your availing of a car parking space.
The Guidance is arranged in a Questions and Answers format and is available here