Those are the issues people are reporting.
Takes ages to sign in,takes ages to load games,get disconnected from xbox live randomly. I get the black screen thing as well. Tonight I had 2 messages saying the COD servers were unavailable even though my friend were still playing.
There are loads of posts about it on the talktalk and xbox forums.
which I got from the xbox forums and I haven't had a single disconnect all night. It's been a proper pwning night with all the noobs on Black OpsThe other thing I did that possibly made a difference was deleted the last update and reinstalled it, to do this go to system settings, memory, then hit the following: LB RB X LB RB X, after you delete it your xbox will restart and says theres an xbox live update, don't expect immediate changes though, mine stayed the same up until a hour or so after I did it, may be a coinsidense
I'm on TalkTalk LLU here, no problems at all with Xbox Live.