The table below provides a break down of the 2012 GS Payscale by hourly and overtime rate. All rates were effective January 2012. Even though rates were frozen at 2010 levels, pay raises can still be provided through within grade adjustments and promotions.See this article for 2012 GS Pay on an annualized basis and this article for a discussion of 2013 pay rates.
Currently, it looks like 2013 GS payscale rates will remain unchanged through April 2013 due to sequestration measures that have frozen budget and government spending. However I will update as more information comes to hand and encourage you to subscribe (free) to get the latest updates
Table Key : Hourly Basic (B) Rates by Grade and Step; Hourly Overtime (O) Rates by Grade and Step
Source : OPM.gov