Getalifeing occurs in Grand Theft Auto 4 free mode. In order to getalife someone you call them in the game and convince them to enter your helicopter usually under false pretences (I.E. telling them that there is a secret room in the GTA4 map) Once they are in your helicopter you bring them to the top of the getalife building convince them to exit the helicopter and take off leaving them there.
ZOMFG! Did you guys see that N00B falling from the sky? He must have gotten Getalifed!