[This is LEGACY information]
By default, first thing each day (of use) iThoughts will zip up all your maps and save them in a special folder on your iOS device. It will keep the last 7 archives on disk. If you want to recover a deleted map (after emptying the Trash) or a previous version of a map then you can download one of the 7 archives, extract the map and then upload it back into iThoughts.
To download an archive:
Ensure iOS device and desktop PC/Mac are on the same WiFi network.
Enable Browser Transfer from the System Settings menu.
Launch Browser Transfer from the Share menu.
Launch a browser on your Mac/PC and enter the address indicated (exactly as it appears on screen - including the :44444 on the end) then click on the 'Archive ZIP' link and then on the archive that you wish to download. On a Mac, the zip file will be downloaded and unzipped into your Downloads folder. On a PC you may need to unzip the file yourself (double clicking will usually suffice.) You should now have a folder structure containing all your maps (ITMZ files.)
To restore a map, click on 'Choose Map' then the ITMZ file then 'Upload Here' and the map will be uploaded back into iThoughts.
NB: The archives should not be considered a 'backup strategy'. If you delete the app then the archives are deleted also. See here for more info on backup strategies.