MCE keyboard shortcuts

Move up UP ARROW
Move down DOWN ARROW
Move left LEFT ARROW
Move right RIGHT ARROW
Select ENTER or SPACEBAR
Jump back one page at a time PAGE UP
Jump ahead one page at a time PAGE DOWN
Start Media Center Windows logo key+ALT+ENTER (pressing this in MC will take you to main menu)
Go back to the previous screen or backspace a single character in Search BACKSPACE
Toggle full screen mode or window mode ALT+ENTER

Change channels
Change to a specific channel The number for the channel you want
Move up one channel EQUAL (=) or CTRL+EQUAL
Move down one channel MINUS (-) or CTRL+MINUS

Menu shortcuts take you directly to the main menus for feature areas.
To go to top level menus for
My TV CTRL+SHIFT+T
My Music CTRL+M
My Videos CTRL+E
My Pictures CTRL+I

TV and DVD menus
To go to TV and DVD menus for
Guide CTRL+G
Record CTRL+R
Details CTRL+D
DVD Menu CTRL+SHIFT+M
Recorded TV CTRL+O
DVD Audio CTRL+SHIFT+A
DVD Subtitle CTRL+U

Transport controls control the playback of your media.
Pause CTRL+P
Play CTRL+SHIFT+P
Stop CTRL+SHIFT+S
Replay CTRL+B
Skip CTRL+F
Rewind CTRL+SHIFT+B
Fast Forward CTRL+SHIFT+F
Mute F8
Volume Down F9
Volume Up F10


Related Info on the Microsoft Site :

http://www.microsoft.com/enable/products/keyboard/keyboardresults.asp?Product=42