There is also such a thing as a Greek push-up. Then there are triangle push-ups, full planche push-ups, and the list becomes endless.
Indisputably, the push-up is one of the most versatile and most effective exercises. Just about anyone, at any age, at any fitness level can do a variation of the push-up to build upper body strength.
A first-timer may want to a try an incline push-up, commonly called a girlie push-up, wherein the body is pushed off the floor by the hands but the knees remain on the ground. If that is still too difficult then one might try starting in the up position of the incline push-up and slowly move to the ground. (This action is called a negative and can be applied to most exercises at any stage of fitness.)
Once some degree of muscle control is established, the standard push-up will build a great deal of muscular strength in the neck, shoulders, arms, chest, abdominals, and even the back. While they are difficult, as any martial artist who have been punished with them can attest, the result of the routine practice of this exercise is undeniable.
If done incorrectly a push-up may cause minor injury to joints, so start slow and controlled. Watch a few videos on different kinds of push-ups, and always check with your physician before starting a new exercise.
Here is a list of some push-up videos from Youtube.