MyOS is described as 'lets you easily enable or disable features on your iPhone, iPod Touch, or iPad' and is an app in the OS & Utilities category. There are three alternatives to MyOS for iPhone and iPad. The best alternative is Winterboard, which is free. Other great apps like MyOS are Springtomize (Paid) and BossPaper (Free).
Give your iPhone or iPod Touch a graphical overhaul! WinterBoard allows you to customize the appearance of your jailbroken iOS device and install third party themes. You can only get Winterboard from Cydia (on jailbroken iOS devices).
Springtomize gives you an all-in-one settings page for tweaking the homescreen the homescreen of your jailbroken iPhone. You can disable elements you don't use, or customize the look of the icons, the dock, the folders, the status bar, and the lock screen.
BossPaper is a wallpapers manager for your jailbroken iPhone or iPod Touch that uses very little processor or memory. You can set wallpapers for 1st-gen or 2nd-gen devices which don't support wallpapers in iOS 4, or rotate wallpapers as a slideshow.