I had no problem changing your long URL link to a short URL link on your post here:

http://fse.luniz.org/viewtopic.php?t=404

If you look when posting a message, and you put your mouse over the URL button, it tells you how to:

Insert URL: [url]http://url[/url] or [url=http://url]URL text[/url]

For example, 
[code:1:b0e1cd0f0f]&#91;url&#93;http&#58;//www.yahoo.com&#91;/url&#93;[/code:1:b0e1cd0f0f] will just display [b:b0e1cd0f0f]http://www.yahoo.com[/b:b0e1cd0f0f] in a post.

[code:1:b0e1cd0f0f]&#91;url=http&#58;//www.yahoo.com&#93;Visit Yahoo&#91;/url&#93;[/code:1:b0e1cd0f0f] will display [b:b0e1cd0f0f]Visit Yahoo[/b:b0e1cd0f0f] in a post which is a link to [b:b0e1cd0f0f]http://www.yahoo.com[/b:b0e1cd0f0f]