Put a text widget into your sidebar and copy and paste the code below into the text area on that widget, save and then take a look at it on your blog. If it works for you, then you can just delete the image widgets you have now.
<p><a href="http://www.twitter.com/acfitness1" target="_blank"><img width="108" height="108" class="aligncenter" title="twitter" src="http://acfitness.files.wordpress.com/2010/09/twitter-100.png?w=108&h=108"></a></p>
<p><a href="http://www.facebook.com/pages/Charlotte-NC/AC-Fitness/112413138814661?ref=sgm" target="_blank"><img height="108" width="108" class="aligncenter" title="facebook" src="http://acfitness.files.wordpress.com/2010/09/facebook-100.png?w=108&h=108"></a></p>
<p><a href="http://www.youtube.com/watch?v=aD0VH_4V55o" target="_blank"><img height="108" width="108" class="aligncenter" title="youtube" src="http://acfitness.files.wordpress.com/2010/09/youtube110.png?w=108&h=108"></a></p>
<p><a href="http://www.vimeo.com/acfitness" target="_blank"><img height="130" width="130" class="aligncenter" title="vimeo" src="http://acfitness.files.wordpress.com/2010/09/vimeo150.png?w=130&h=130"></a></p>