There are 15 previous versions of this script.
// ==UserScript==
// @name Twitter Lines
// @namespace http://userscripts.org/users/113977
// @description Restore line-breaks and multiple spaces in tweets by converting them to HTML breaks and non-breaking spaces
// @include http://www.twitter.com/*
// @include http://twitter.com/*
// @include https://www.twitter.com/*
// @include https://twitter.com/*
// @include http://www.brizzly.com/*
// @include http://brizzly.com/*
// @include https://www.brizzly.com/*
// @include https://brizzly.com/*
// @include http://favstar.fm/*
// @version 0.3.2
// @date 2011-01-06
// @creator Jeremy Cutler
// ==/UserScript==
var newS = document.createElement('style');
newS.setAttribute('type','text/css');
newS.innerHTML = '.entry-content, .tweet-text, .theTweet { white-space:pre-wrap !important; }';
document.getElementsByTagName('head')[0].appendChild(newS);