Watch the Common Place online guitar lesson by Brad Carlton from Chord Studies: Beginner Chords Vol. 1
Here's an example that uses a common progression of two chords: a G and an E Minor. Each chord should be played for four beats. In this example, it's very important that you maintain your second finger in contact with the fifth string in the second fret when you change chords. This is another example of using a "pivot finger" like we used in the last example.