Вот код:
x=new Date("2011-08-02T00:00:00-00:00")
str=(x.getUTCMonth()+1)+"-"+x.getUTCDate()+"-"+x.getUTCFullYear()
Или:
x="2011-08-02T00:00:00-00:00"
x=/^(\d+)\-(\d+)\-(\d+)/.exec(x)
if(x){
str=(parseInt(x[2],10)+"-"+parseInt(x[3],10)+"-"+parseInt(x[1],10))
}