Your entire database can be backed up to an external file or restored from a file on a webserver.

Tap Backup Database while on Settings tab → Exporting & Backup and enter an email address to email a backup of the entire database. These files are typically very small and easy to email.
Your previously backed up Jobs database file will have to be uploaded to a web server or FTP site. Apple's iDisk can be used for this, as can a lot of other free services available online if you don't have a server to use. Tap Restore Database while on Settings tab → Exporting & Backup and enter the URL of the backup file.
Warning: Please ensure you backup your data as often as possible, both by syncing to iTunes or via the backup function in Jobs itself. Note that Bjango cannot take responsibility for any data loss. Use Jobs at your own risk.