I went ahead and created this little program in about an hour to move my files from the Blosxom Blogging system to the Simple PHP system I am using now. The code is pretty straight forward, not commented and very crude but it does the job!
If you want to use it go ahead, no disclaimer but use at your own risk.
You will most likely want to modify the getCategories() method and put your own categories in it.
You can get the zipped sources here.