I've used This in the past with a reasonable degree of success
It starts off free but after a period of time it starts to ask you to put in the answer to a 'simple' calculation before conversion, a calculation that you will need either a maths degree or a sound knowledge of excel to calculate but if it's a one off project then fill your boots before the trial period expires
-------------------- XP Home
Office Pro + FrontPage, IE6
AVG, Zone Alarm