Conversions - How do I convert from my current software to SMF
From Online Manual
There are many converters available to help you migrate your current forum to SMF without losing your old members, subjects, messages, and other things. Please visit the Converters List for a list of currently available converters.
Try also browsing the Converting to SMF board on our community support forum if you have any question or trouble in converting your forum. You may, in addition, use that board to request the coding of a converter which does not yet exist.
For documentation on converting, please see the Converting to SMF page.