My FI and I are telling our parents first hand, however my mother makes a huge deal anytime anyone in the family announces anything via email or Facebook, which is how we found out about the birth of my cousins' last three children. I am the youngest cousin and am fairly close to my family. We are also waiting until I graduate from college in 2012 to wed, even though he is graduating this spring.
I'm just wondering what the best and most proper way to tell all of the aunts, uncles, and cousins other than waiting until we see all of them on Thanksgiving.