How to install stock app on custom rom? I flashed a custom rom but I didn't like it's default Contacts app (I prefer the stock app). 

How can I install the stock Contacts app in a custom rom?

BTW the ROM I have is CM7-APOCALYPSE-FINAL
Simply copy the desired app from your favorite ROM (the apk is usually in /system/app) to your destination phone and then install it normally.