It depends on what you want to say after that. If you want to say: "I'm getting/becoming angry"="Me estoy enfadando". "I am becoming part of the family" = "Estoy convirtiéndome en parte de la familia". "I am getting my diploma"= "He conseguido mi diploma"

Here's an italki article you may find useful :) http://www.italki.com/article/159/to-become-a-very-interesting-verb-for-spanish-students#.U-8ii6PW4zI Cheers.

I,m getting old=me estoy haciendo mayor It,s getting dark=se está haciendo tarde I,m becoming rich=me estoy haciendo rico So you could use "me estoy + gerundio" o "se está + gerundio" Cheers!