I have a S2. I want to root my phone to use the amazing apps out there Not to install custom roms. Can i still get access to the official updates from Samsung ?
I recommend using OTA RootKeeper. From the app description:
This application makes a backup or a protected backup of your device's root. This device must already be rooted: OTA RootKeeper doesn't have the ability to root devices.
It allows you to temporary un-root your phone for OTA updates and then restore back root.
Before installing please check this XDA thread.