Geezer - you don't need flt planning software (though it makes it a lot quicker), it's perfectly ok to do it long hand. The main problems though are access to the AFTN network if you haven't got it, and access to all the FIR/airfield addresses. Just grab yourself the applicable ICAO docs as vipero mentions and off you go. Me personally I prefer to do it long hand especially if its somewhere I've not been before, there is some well dodgy software around.
cheers