A review of the My Little Pony Musical MP3 Microphone:  
http://www.target.com/p/my-little-pony-microphone/-/A-14067246

(good luck finding one in stores, I had to go to four Targets to find one)

I picked up one of these microphones today to give it a whirl.  I'm quite impressed by the thing overall.  It has two modes, a Song mode and an MP3 mode.  In the Song mode it plays one of two pre-recorded songs and in the MP3 mode it lets you connect to an audio source.

The Song mode has two pre-recorded songs, the MLP:FiM Theme Song and the song 'Cupcakes'.  The microphone also has the ability to be attached to an MP3 player (or any audio source that takes a standard 3.5mm audio plug).  In both modes you can push the 'microphone' button and sing into the mic element and your voice will be amplified 'across Ponyville' according to the packaging.

Yes I know that I said the microphone had the Mane 6 on it but upon further review it does not have Applejack on it, go figure.

Thanks to Music By Octavia for his wonderful kazoo arrangement of 'The Perfect Stallion'

http://www.youtube.com/user/MusicByOctavia
http://www.youtube.com/watch?v=91ZB8_25Yyk&feature=plcp

http://www.mlponies.com