This little script generates links from usernames and hashtags to Twitter.

tuitlink.js

/*
* Tuitlink 
* by Alberto Mtnz (https://github.com/threkk/scripts)
* This little script generates links from usernames and hashtags to Twitter.
* To use it, just import the library:
* <script type="text/javascript" src="twitlink.js"></script>
* It is under a MIT license. 
*
*/

/*jslint browser:true */
var tuitlink = {
    load : function () {
        'use strict';
        var body, username, hashtags;
        username = /\s@[a-zA-Z0-9_]{1,15}/g;
        hashtags = /\s#[a-zA-Z0-9_]+/g;
        body = document.body.innerHTML;
        body = body.replace(username, this.users);
        body = body.replace(hashtags, this.htags);
        document.body.innerHTML = body;
    },
    users : function (match) {
        'use strict';
        var m, r;
        m = match.slice(2, match.lenght);
        r = " <a href='http://twitter.com/" + m + " '>" + match + "</a>";
        return r;
    },
    htags : function (match) {
        'use strict';
        var m, r;
        m = match.slice(2, match.length);
        r = " <a href='http://twitter.com/search?q=%23" + m + " '>" + match + "</a>";
        return r;
    }
};

window.onload = function () {
    'use strict';
    tuitlink.load();
};