If You want to modify this Geeklet, open the file with TextEdit, then edit this line:
say hey Apple, how are you?? afplay /Users/fikrferd/Documents/enter-mac.mp3
Change the sentence as you want after the word 'say'. So if you want your Mac say: "Hi, I am Your mac!" change the first line to:
say Hi, I am Your mac!
If you want to play your sound, put your MP3's path to the second line after the 'afplay' word.