function OnGUI()
{
if(GUI.Button(Rect(90, 180, 260, 60), "Start!"))
{
PlayMusicThenLoadLevel();
}
}
function PlayMusicThenLoadLevel()
{
audio.Play()
yield; //not sure this is needed
while(audio.isPlaying) //if you want to wait until the end of the audioCLip before you load. Else, skip this.
{
yield;
}
Application.LoadLevel(yourLevelNb);
}