See, that's a very vague idea of what you want to do - and it can be interpreted in various ways >.> Perhaps you should be more specific.
Anyway...

If you mean you want to delete a subscription that you no longer want to read, go here: http://www.xanga.com/Private/subsactive.aspx and click delete!

If you mean you want to delete someone who is subscribed to you and no longer want them to see your stuff - you can block them here: http://www.xanga.com/Private/Subscribers.aspx

Or, if you meant that you wanted to delete your xanga altogether - go here: http://edit.xanga.com/shutdownquiz.aspx to take a short quiz and delete!

Good luck; I hope I was at least somewhat helpful (:

按我 呀賴啦;]♥