This utility allows you to download your data from any XMPP account, into a file. It also allows you to upload your data to a new account and inform your contacts.
Note: If you want to move your data to a new account, make sure you have created it already and have your credentials ready! You will need them to complete the migration.
Need help choosing a new provider? Check out joinjabber.org for free public providers or Snikket if you want to manage your own private service.