To install PiTFT on any Raspberry Pi SD:

• Download and run the PiTFT-helper;

curl -SLs https://apt.adafruit.com/add | sudo bash
sudo apt-get install -y raspberrypi-bootloader
sudo apt-get install -y adafruit-pitft-helper	

• For PiTFT2.8":

sudo adafruit-pitft-helper -t 28r

• For PiTFT3.5":

sudo adafruit-pitft-helper -t 35r

• Reboot.

Easy install SD images:

• for PiTFT 2.8"
• for PiTFT 3.5"

Mods required for boot into graphical desktop! (Pi 2 - 3.5")

• Create a config file;

sudo nano /usr/share/X11/xorg.conf.d/99-fbdev.conf

• Enter the following content:

Section "Device"  
  Identifier "myfb"
  Driver "fbdev"
  Option "fbdev" "/dev/fb1"
EndSection

• Save and reboot.