By definition, a Universal Binary (when talking about OS X applications) refers to an application that is compatible with both the Intel and PowerPC processor architectures. Therefore, each UB application is a little bit larger to support each architecture. Xslimmer is a unique shareware (cheap too) application that removes the excess fat from your UB's depending on what architecture you're running.
The Xslimmer interface in action. I already slimmed the first two applications shown.
For example, if you're on an Intel Mac, drag a Universal Binary application onto Xslimmer, in a very AppZapper-esque action, and Xslimmer will let you know how much space you can save. If you're up to it, just hit the "Slim!" button. However, unless you have a lot of applications, I don't think Xslimmer will be able to save much space. You're probably better off deleting the podcasts you don't listen to in iTunes. [hat tip to Chris Messina]