Saw this tip this morning in TNW.
MakeOrv (MakeOvr) is a nice tool to create "dummy" icons in your iPhone home screen that will capture some room and let you position commonly used apps in a lower area of your home screen.
How is it done? As you may or may not know, there is a simple way to place websites as "WebApps" in the home screen. Each WebApp gets an icon that represents the web page and takes you straight to the site. There is also a way to set this icon by applying a small attribute to the website. MakeOvr uses this trick to let you select a background and then apply some transparent "dummy" icons in the areas where you want to "replace" real apps with empty spaces.
Sounds a bit complicated but it's really very simple. No jailbreaking is needed.
Here's a short video: