Extreme 4 in Line HD app for iPhone and iPad

This version is for iPad only.

"Connect Four (also known as Captains Mistress, Four Up, Plot Four, Find Four, Fourplay, Four in a Row and Four in a Line) is a two-player game in which the players first choose a color and then take turns dropping colored discs from the top into a seven-column, six-row vertically-suspended grid. The pieces fall straight down, occupying the next available space within the column. The object of the game is to connect four of ones own discs of the same color next to each other vertically, horizontally, or diagonally before your opponent. There are many variations on the board size, the most commonly used being 7x6, followed by 8×7, 9×7 and 10×7. The game was first sold under the famous Connect Four trademark by Milton Bradley in February 1974."
Source: Wikipedia

If you are looking for a casual game, this is a great title to spend good hours playing.