Actually, you don't have to jailbreak for access to the file system any longer, but You do have to use a separate app... which is still ultra-BS in my book. Behold, PhoneView. Access to the entire iPhone/iPod Touch filesystem.
Q: Once I copy files to the iPhone, can I view/access the files through the phone? A: There's no way to access PhoneView's copied files via the iPhone's interface. However, PhoneView can copy the text from many file formats directly into the iPhone's Notepad program.