rooting voids the warranty - although some service center might not even check it.
removing root and going back to stock is not as simple as in the iphone or ipad where you just connect to pc/mac and restore via itunes.
Before rooting be sure you get familiar with adb commands and fastboot. Know your device well and have a stock rom of your device before hand. A good source of information is Android & Windows Phone: Tablets, Apps, & ROMs @ xda-developers