The only mike I found at Macally is this.
http://www.macally.com/EN/Product/ArticleShow.asp?ArticleID=171
It says it works with iPod 5G, iPod nano 2G and iPod classic -- doesn't say it works with ipod touch or iPhone.
Why do you need to use the ipod Touch's built-in speakers, instead of hooking up external speakers through a microphone adapter?