The interest rate rises/falls are supposed to be based on the basket of goodies that determines inflation. Not the bleeding rises in property prices. This increase, on the basis of trying to reign in housing price increases, is just another example of a regulatory body loosing sight of it's charter and stepping into areas it should keep the fark out off.
The people this will impact on most are those that already have mortgages. This will reduce the amount of money circulating within the economy (at a time the economy needs stimulus), will impact on new building projects and will have a negative impact on the economy going forward (where the inflation rate does not warrant it).
At this point I begin to wonder if the Reserve Bank feels it has an obligation to take over where John Howard left off.