CiviCRM Community Forums (archive)

Not sure the best way to handle site content. But for CiviCRM, it shouldn't be too painful, as the schema is virtually identical, including the table names (Civi in Joomla doesn't prepend the standard jos_ prefix).

I haven't actually done this, but I suspect you'd follow a modified version of the moving site instructions:
http://wiki.civicrm.org/confluence/display/CRMDOC/Moving+an+Existing+Installation+to+a+New+Server+or+Location

My short modified version (again, untested) would be:

1) run a db dump of your civicrm tables from drupal using REPLACE (instead of INSERT) -- data only. or if you have custom data (which will have their own tables) use the IF NOT EXISTS option for structure export
2) install a clean copy of civicrm in your joomla install
3) import your drupal civi dump file to your joomla db, thus replacing the default data
4) run the update config url: http://<joomla_site>/administrator/index2.php?option=com_civicrm&task=civicrm/admin/setting/updateConfigBackend&reset=1
5) try getting into civi in the backend. go to global settings and make sure your directory and resource url values are correct

then report back and let us know if it worked!