Connect 4

Connect 4
https://market.android.com/details?id=cn.bluesky.fourinaline

Connect 4
http://www.appbrain.com/app/connect-4/com.mobialia.fourinarow

Super Connect 4
http://www.appbrain.com/app/super-connect-4/com.canadadroid.connect4

Connect-4
http://www.appbrain.com/app/connect-4/com.softmimo.android.connectfour

Computer Flash version
http://www.mathsisfun.com/games/connect4.html

Description
Also named "Four in a line". The goal is to connect a line of four horizontal,vertical,or diagonal chips before your opponent does. Tap one the row you wish to drop your chip in.
Play with machine AI with 4 difficulty levels, or play over internet with other players.