Outook Express dbx files to Outlook pst

Is there a simple way to get my users email files that are stored in .dbx files created by Outlook Express into their Outlook files. I will award points only for a workable solution as my users are using Outlook via Citrix in a terminal server type environment and the best help I can get from users is for them to “zip” their dbx files up to me to “do” the import.
Any help?