TinyURL.com is a website that allows you to convert a long url to a tiny one that will not break in email postings and never expire.
However, I don't trust clicking on these types of links, as you don't know everytime what's "hidden" (affiliate/tracking links for instance). But I've seen that they've introduced a new feature that allows you to preview the link before visiting it. This is a great improvement and you can turn this feature on by visiting http://tinyurl.com/preview.php and clicking on Click here to enable previews (make sure you allow cookies).
After that, each time you'll click on a tinyurl link you'll be directed first to a preview page, like the one you see below: