update to question :
i played around with adding the extention .mov to all the places in all files of the nextgen folder where .jpg and .gif etc were listed.
i think the files are in the admin folder, but i did a dreamweaver 'find' for .jpg.
and it works. you can upload a .mov file and place it in a gallery i called 'movies'.
the only problems are :
1. you get a unrecognized file type error when you upload it but you can still upload it. this can be sorted out by adding more code in a page somewhere in admin but i can't really be bothered tonight to find out where.
2. you don't get a thumbnail. i reckon a default movie image would be a good start if nextgen gets the ability to upload movies and music file types in its next update. even better would be a random screenshot at say, .10 secs into every movie
if anyone has already tried this and done better, i'd love to hear how.
i am very curious why nextgen programmers didn't release this capability into there latest update. for a programmer i would say it was an easy fix. maybe they will next time. ?