Shoulders

For strength conditioning you could try doing Push Presses and Military Presses. If you're more concerned with developing power, push presses may be better since it's more explosive. You could also just stick with the classic clap push-ups; they work the shoulders as well.

http://www.exrx.net/WeightExercises/OlympicLifts/PushPress.html
http://www.exrx.net/WeightExercises/DeltoidAnterior/BBMilitaryPress.html

 

for explosive power for shoulders try push presses, or jerks.
learn proper technique.

Clap pushups are also good, full range of motion

 

Cleans, Hang Cleans, Power Cleans, Hang Power Cleans, Push Presses, careful with these exercises, maintain good form and don't use too much weight.

 

Move the other shoulder, otherwise theres no movement shoulders dont move.If they do youve got problems.

 

waha??? We're we meant to decode that? Or is that Floyd Sr talking?

 

Most power comes from your legs, which is why you pivot and step into punches

 

There is a reason sports teams from all levels have their players do cleans, jerks, and snatches.
And like paloalto said, punching power comes from legs so you could also try these: depth jumps, box jumps, hurdle jumps.
Here’s a website that lists most of what’s been already mentioned:
http://www.exrx.net/Lists/PowerExercises.html
And to repeat what pugilist said, you should always follow strict form and don’t go overzealous on the poundage or this could happen to you:
[ame]http://www.youtube.com/watch?v=MxURCBEZfZg[/ame]

 

Did that guys shoulder pop out?

 

It looks like his elbow bent the other way and got dislocated. Here's a better look:

[ame]http://www.youtube.com/watch?v=uI0Zl-tMRf4[/ame]

 

Thats horrible, must have been some weight on that bugger. Thats what would happen to every joint in my body had i attempted that!

 

Ouch!!!! That video ruined my day xD

 

Personally I see much bigger gains in power from practising good technique rather than hundreds of pushup's etc.

Proper hip rotation, stepping into the punch etc

Its a boring answer I know but hey!

 

Out of curiosity, why would you want to increase explosive power in the shoulders? I take it you're not a boxer...?