You can't do that I'm afraid. iCloud is essentially meant to be a backup / synchronisation tool for iOS devices and Mac OS X computers (though there's some limited synchronisation with Windows e.g. calendars and contacts with Outlook and web bookmarks). For a standard user, it ensures your iPhone's details are constantly backed up and can be restored at any time - very useful. It also means any purchases made on an iPhone can easily be downloaded to another iDevice without any charge - it's just seamless.
The beauty of it as a Mac user is, I can make changes on my Mac such as in my contacts list, and they're automatically updated on all my Apple devices (e.g. Macbook Mini, Macbook Air, iPhone and iPad (if I had one)). Same goes for adding a bookmark to Safari - I do this on one device and that bookmark is available on all my devices without me having to do anything. There's other features like Photo Stream which mean photos are instantly available on my Mac in iPhoto once I've taken a photo on my iPhone - again, it's just seamless. Same goes for certain documents e.g. documents created in any of the iWork applications.
The iTunes Match service will allow you to sync your music library to iCloud, but it will only be stored in 256 kbps AAC - there's no option to do this in lossless. I suspect this is because the amount of space this would take up for potentially millions of users would just be too much of a strain on Apple's storage in their Data Centres, so it's just been ruled out (at this stage).