Why Can't I See The AirDrop Menu in OS X Lion?
If you have access to AirDrop, you should be able to see it by going to the Finder and clicking on the Go menu. If AirDrop isn't listed there you cannot use it on your Mac.
Unfortunately, AirDrop does not work with every Lion compatible Mac. It must be the same as or newer than the Mac models listed below.
MacBook (Late 2008 or newer)
MacBook Pro (Late 2008 or newer)
MacBook Air (Late 2010 or newer)
Mac mini (Mid 2010 or newer)
iMac (Early 2009 or newer)
Mac Pro (Early 2009 with AirPort Extreme or Mid 2010)