i havent seen much sites gathering the walking dead easter eggs. list of easter eggs i know:

1. in season 2 daryl carries merles drug bag when t-dog is injured, at the bottom of the bag there is crystal meth, from another amc show breaking bad.

2. in volume 1 of the comic when rick is riding a horse to atlanta on the highway when you see the whole city you can see homer simpson in a billboard.

3. the place andrea and shane look for sophia in season 2 is wilthshire estates from the comics.

4. in tv and comic when carl is first time introduced he is wearing a science dog t-shirt (its another robert kirkmans comic book).

5. when tyreese is found alive in the prison gym, a dead walker is giving tyreese the middle finger.

6. season 2 dvd has a hidden easter egg clip showing lori crashing the car, but instead of walker there is a dinosaur running across the street (not kidding)

not sure but in season 2 nebraska did dave and tony mention/refer alexandria safe zone? share on the comments all easter eggs in the tv series, comics and the game!