BootstrapCDN is supported by JSFiddle, you just need to paste in the relevant URLs.
In the external resource field/box enter each of these URLs* and hit +:
http://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/css/bootstrap-combined.min.css
http://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/js/bootstrap.min.js
The result of which is: http://jsfiddle.net/v9ec3/1/
Which then allows you to post your HTML/CSS/JS as required. Edit away and click update when finished to give you a URL that you can paste anywhere (including here!). Note you don’t need to reference it via link.
****Note:** The above bootstrap version URLs (2.3.2) are pasted from http://www.bootstrapcdn.com at the time of the question*