the only way I know how to do it would be download the free trial of office (so you get outlook) open the pst file in outlook while it is running as trial and then use the export function in outlook to export them in outlook express format (or windows mail if outlook 2007 will do it, either will work) you can then import the mails into windows mail using the outlook express format you've just exported.
There is no direct way to do it.
http://trial.trymicro...ficepro&culture=en-GB