Apple iTunes can be of much help and usefulness, not only it plays songs but also gives you several features such as upgrading your iPhone and iPod Touch OS, downloading apps from Apple stores etc. In addition to that you can create a backup copy iPhone/iPod just in case any thing goes wrong with your iPhone/iPod.
The disadvantage with iTunes is that any backup created by iTunes can be extracted using iTunes only. But this seems inconvenient. If you are looking for a way to extract backup copy created by iTunes without using iTunes itself, then you should use iPhone/iPod Backup Extractor as an alternative.
iPhone/iPod Backup Extractor is a free application developed by Pádraig that not only helps you in extracting iPhone OS backups created in iTunes but also makes it usable in Mac OS X leopard environment. In addition to that you can extract SMS messages, Call History and Notes from backup.
Lastly, using iPhone/iPod Backup Extractor can also be helpful from a developers perspective. It is designed to run on Mac OS X Leopard only and is is compatible with latest Apple iTunes 8.1.