One of the easiest ways to display your FeedBurner subscriber count number in plain text is to use the Feed Count plugin by Francesco Mapelli. I have been using this plugin at Perishable Press for a long time, and it has always been great. Unfortunately, Francesco's site seems to be suffering from malicious behavior these days, with tons of spam comments, weird files that are automatically downloaded to your computer, and even one of those scary warnings from Google: "Reported Attack Site," or whatever it says.
In any case, the Feed Count plugin is too awesome to let disappear into the ether, so it will be hosted here at Digging into WordPress until Francesco's site checks into a rehab center and cleans itself up. Hopefully that will be sometime soon. In the meantime, to download a squeaky-clean copy of the Feed Count plugin, simply click on the title of this post.