We just celebrated my youngest's 4th birthday. He chose "dinosaur" as the theme and it was a great party. One way I help to create the party mood that matches the theme and age group is to make a playlist on YouTube (They should pay me, seriously. I'm on there everyday. free music = love). For the last two weeks we have been dancing around the house to this number - the favorite on this list.
Sample the entire Preschool Dinosaur Party Playlist here. There are dino songs, some of my son's current pop favorites, and some sound track background music numbers. Enjoy!