My iPod touch is full. Can I have my music get stored in the cloud to give me more space available?

You can redownload some itunes purchases frmo icloud.

All of your music should be on your computer. Make playlists and sync whatever you like to your ipod. You can change what you sync whenever you like.

Delete iTunes purchases you do not need on the iPod at this moment if they can be redownload. See:

Downloading past purchases from the App Store, iBookstore, and iTunes Store

Note if you delete apps, and then reinstall them you will lose app date unless the data is stored on a server.