From Sprintfeed,
"All good things must eventually come to an end. This age old saying definitely applies to smartphones."

Combined with other End Of Life (EOL) timelines:

Being Replaced Now
Droid X being replaced by the Droid X2
Verizon LG Ally
Verizon LG Vortex (Optimus V)
Verizon Fascinate Galaxy S replaced by Samsung Stratosphere Galaxy S II

September
White HTC EVO 4G replaced by EVO 3D
BlackBerry Bold 9650

October
Black HTC EVO 4G replaced by EVO 3D
Samsung Epic 4G replaced by Epic 2
BlackBerry Curve (Graphite Gray)
HTC Thunderbolt to be replaced by the HTC Vigor
LG Revolution replaced by the LG Revolution 2

These discontinued phones are less that a year old.