New Sling Player out for WM6 - get it here:
http://us.slingmedia.com/object/KB-005111.html?page=2
I was on the Beta team with the 6700 and 6800 for a few days and it rocks!
By default it will go Landscape on what we 6800 users would call up side down according to the way the key board slides out - but you can modify that. I'll post how later.