Friends, please calm down. If you are muslim and are offended by this, please consider the following in a cool fashion.
There are certain things so holy, that God Himself protects them. The Kaaba, the Quran, the Prophet and his Family are some examples. Now, throughout history evil people have attempted to destroy or insult these holiest of holies. However, the Quran itself tells us what happened to them. Recall the time when Abraha, a mighty King, decided to invade Mecca and attack the Kaa'ba. The Prophet's grandfather, who was the Keeper of the Kaa'ba and a monotheistic Haneef (before the time of Islam), said openly, "The Owner of this House is its Defender, and I am sure He will save it from the attack of the adversaries and will not dishonor the servants of His House."
You all know what happened after this. When the Prophet's grandfather, Hazrat Abdulmuttalib entrusted the defence of the Kaaba to Allah, Abraha was destroyed forever.
It is our belief that the Prophet and his family are the beloveds of Allah. If it angers us to see these cartoons being published, imagine how much it angers God. Why should we attempt to lessen the punishment of these swines by taking revenge as humans, when Allah has told us in the Quran:
[Yusufali 8:30] Remember how the Unbelievers plotted against thee, to keep thee in bonds, or slay thee, or get thee out (of thy home). They plot and plan, and Allah too plans; but the best of planners is Allah.
Allah has promised us the day when no one will be able to abuse the Prophet or his true ummah:
[Yusufali 66:8] O ye who believe! Turn to Allah with sincere repentance: In the hope that your Lord will remove from you your ills and admit you to Gardens beneath which Rivers flow,- the Day that Allah will not permit to be humiliated the Prophet and those who believe with him. Their Light will run forward before them and by their right hands, while they say, "Our Lord! Perfect our Light for us, and grant us Forgiveness: for Thou hast power over all things."
Why are we then, so impatient? Let these swines continue their evil so that their punishment is made ever more miserable. Why should any muslim kill these people? Let them dig a deeper hole for themselves. The more punishment they get, the better. These are people from amongst the Jahiliya... they only deserve to be ignored.