Watch the Suspended Chords online guitar lesson by Ravi from Guitar Lab: 30 Rock & Pop Progressions
Suspensions are another way to suggest a chord change using the I, the IV, and the V. However, instead of actually making those changes, a suspended chord allows you to borrow notes from the IV and V chords and impose them on the I. By doing so, you retain the grounding of the root chord, the I, throughout the progression but create interest and movement by hinting the chord movements that the ear expects to hear. Plus, they are easy to play because only one finger moves which also means that there is a lot of continuity in the sound.
Examples: She Talks to Angels, Midnight Blue, Free Fallin'