The interest rate of the housing loan is at its lows nowadays. If you have taken your loans years ago, you should consider to re-financing now. There are banks which offer Base Lending Rate minus 2-3% interest rate.
If you seriously considering that, there is one blog which describe in detail what you should consider when you want to refinance. Some of you might say that it is very troublesome and time consuming to do that. But if you think of how much you could save, I would say that it is worth spending your time. However, if you have already decided to sell your properties, forget about it. It is because the bank will have the clause to bind you to the loan and you need to pay penalties if you settle the loan early.
Well, enjoy and start to shop around.