If you are looking to get more apps in the dock at the bottom of your screen to allow quick and easy access to your favorite apps - one thing you can do is jailbreak and install the app - 5 icon dock - which per its name allows 5 icons in the bottom dock.
However if you want more than 5 iCons on your iPhone or iPod touch or more than 6 on your iPad - one thing you can do is to simply put a folder in the dock. Then you can put 12 of your favorite apps in each folder.
Thanks to Geoffrey in Huston for originally suggesting this.
