Major Nelson listed the keyboard shortcuts to IM usage on the console on his blog.

What I like about the update so far:

(1) i like the little white arrow that appears besides gamertags on my Friends list that shows which games are joinable .... makes u just want to jump right in and play with them!

(2) i like that the disc tray now denotes what game title is currently inserted in the tray

(3) i like the achievement window / gamerscore summary that appears when u select the disc tray

(4) luuuv the low-power download thingy - first to benefit from this was the GRAW2 map pack

(5) Live Arcade has its own Friends list showing what Arcade games they're playing

I've noticed this since the update - when I'm in the middle of a game and I then go check my Friends list to see their status etc, the blade takes a looong time to go back to the previous screen when I press B. Sometimes so long that it would appear as if it had hung, but in fact it hasn't and goes back to the previous screen after a good 15-20 secs.

Anyone else experience this?

ok thanks guys. guess i'm not alone then .... good to know.

but that means that my isp's been sucky lately then .... never noticed the GUIDE HANG before the update. hmm ....