I just upgraded to Poser 8 and I am trying to render an animation with the compressor depth set at Millions of Colors+ .... but the final rendered quicktime does not have the matte alpha channel it is suppose to have. What gives? Could someone help me, please?

Exactly which codec are you using...? 

 I heard back from Poser 8 SmithMicro tech team. It's a developer issue and they are working on it with apologies. Apparently, the only way to get matte alpha channel in a movie is to render the animation as files (png or psd) with million + and then you'll get the alpha channel. Rendering as a quicktime movie currently is useless if you want an alpha channel.

in P7/8X, the standard method was to save anim sequence as series of tiff files, or to save an uncompressed QT movie, which is the same as concatenating a series of tiff files.  using png file format instead can sometimes have unexpected results in OSX in re: alpha channel and photoshop.

 jpeg 2000 codec supports alpha channel, but I haven't tried outputting from Poser via this codec. I always use Image files for a couple reasons.

1. png = no compression & supports alpha channels. 
2. if there is an error or crash partway through you can start at that frame next time instead of at the beginning.

I am on  a Mac OS 10.5 & use png with Photoshop CS3ext or CS4ext all the time. import the image sequence as a movie, drop a background in and a logo. no problems.