I suspect that it will take some time before the effects of Budget 2011 sink in.

I expect the vast majority of us will only really feel the pinch at the end of January when the new 11 per cent (total) Universal Social Charge and higher PRSI rates (if you earn more than €75,000 or are self-employed) kick in.
You can check how the tax/PRSI/ USC changes will affect you here in the budget annexes: www.budget.gov.ie/budgets/2011/Documents/Part%20C%20-%20Annexes%20to%20SBM%20FINAL.pdf.
In the tables section, find your income category – say, ‘married couple, two children’ or ‘single person’ or ‘pension’.