The newest version (0.9.5) of the I18N plugin (http://get-simple.info/extend/plugin/i18n/69/) supports custom fields: use get_custom_field($name) or return_custom_field($name) to display/get the value for the current language.
You might want to use the new I18N Custom Fields plugin (http://get-simple.info/extend/plugin/i18...ields/100/, based on n00dles101's CustomFields plugin) instead of the CustomFields plugin, as it offers more field types, a GUI to define the fields and is more efficient when used with the I18N plugin. See http://get-simple.info/forum/topic/1537/...-and-i18n/ for more information.
You might want to use the new I18N Custom Fields plugin (http://get-simple.info/extend/plugin/i18...ields/100/, based on n00dles101's CustomFields plugin) instead of the CustomFields plugin, as it offers more field types, a GUI to define the fields and is more efficient when used with the I18N plugin. See http://get-simple.info/forum/topic/1537/...-and-i18n/ for more information.