Tweeterer.js

var text = "Tweet…"

text.replace(/(^|\s)(?:#([\d\w_]+)|@([\d\w_]{1,15}))|(https?:\/\/[^\s"]+[\d\w_\-\/])|([^\s:@"]+@[^\s:@"]*)/gi, function(all, space, hashtag, username, link, email) {
    var res = '<a href="mailto:' + email + '">' + email + "</a>";
    hashtag && (res = space + '<a href="http://search.twitter.com/search?q=%23' + hashtag + '">#' + hashtag + "</a>");
    username && (res = space + '<a href="http://twitter.com/' + username + '">@' + username + "</a>");
    link && (res = '<a href="' + encodeURI(decodeURI(link.replace(/<[^>]*>/g, ""))) + '">' + link + "</a>");
    return res;
});