You can view files from numbers, pages, keynote; contacts stored in iCloud, the iCloud calendar with a computer when you enter
www.icloud.com in a browser and login with your iCloud account.
It's different with photos. iCloud doesn't work like the other online storage possibilities, such as Dropbox, e.g. To view the photos stored in iCloud, you can install the iCloud Control panel on a computer. From there, you're able to save them somewhere else. They won't stay in iCloud forever.
Music/songs you purchased are connected to your Apple ID. iCloud only saves your purchase history, not the music, or apps, or books.
Here's what iCloud backs up:
http://support.apple.com/kb/PH12519
This doesn't mean that you're able to access/view the backup.