Microsoft's 800-BING-411, 800-CALL-411, and 800-555-TELL (Tellme) services are all announcing that they are discontinuing service effective June 1, 2012.

Google's 800-GOOG-411 was discontinued November 11, 2010.
http://blogoscoped.com/forum/174898.html

Alternate free USA directory assistance services:

   800-FREE-411
   800-555-1212

These other services do not offer to transfer a call like BING does. FREE-411 can also search residential listings, which BING did not do.

Google ended their reverse phone lookup web service around February 2011.
http://blogoscoped.com/archive/2011-02-25-n20.html

Google ended Gizmo5 on April 3, 2011.
http://en.wikipedia.org/wiki/Gizmo5

I hope that Google Voice is not in jeopardy.