The long awaited Sling Player Mobile application is now officially available on the Android Market, with download numbers <50 (i.e. moments ago).
Sling promised the app would go live tomorrow but pulled the trigger early and launched it today instead (though I guess it is tomorrow in some time zones).
Update: their Android page is now live.
Things are looking good - so far all 3 reviews are 5 stars, though this may change when we get more installations.