Its like a little show secret for people staying at the deluxes and Fort Wilderness. It pulls out of a canal by the MK and does it thing at GF, then moseys over to the Poly, and I believe it goes to Wilderness Lodge, Fort Wilderness and then the Contemporary before doing a show in front of the MK. I think the resort times are posted on Allears but you can inquire at your resort for viewing times for the above mentioned resorts.
I've read posters say its lame and not worth the effort but for us, we never miss it. It hasn't changed much and heas been running since park origin albeit some hurricane damage that stopped it for a few days. We first were surprised in 1977, staying CR, north garden wing, to hear this loud music from outside. We went down to the dock in our pj's and caught the end and then inquired at the desk what that was all about. We watched it every night after that, once we got the times.
We always catch at least 2 showings while we're there, it great, well done and one of the free things Disney does to add alittle magic.