Previous sin cancelled out?

[glo]

I heard from a Muslim that according to Islam there are certain times/ situations during anybody's life, when all previous sins are cancelled out and count no more.

The times he mentioned were:

• When somebody first says shahadah
• When a woman has given birth
• When somebody dies a martyr's death

Is this correct?
Are there any other times when all previous sin is cancelled out? If so, when?

According to the above information I am assuming that a woman who dies in childbirth or a martyr or somebody who dies just after saying Shahadah would die sinless and go straight to heaven?
Am I right in assuming this or am I misunderstanding?

Thanks! :)

[- Qatada -]

:salamext:

Also these:

`Amr Ibn Al-`Aas (may Allah be pleased with him) narrates: "When Allah guided me to Islam, I went to the Prophet (peace and blessings be upon him) and said to him: 'O Messenger of Allah! Stretch out your hand so that I may pledge allegiance to you.' The Prophet (peace and blessings be upon him) stretched out his hand to me, but I withdrew my hand. The Prophet (peace and blessings be upon him) asked, 'O `Amr! What is the matter with you?' I said: 'I would like to stipulate a condition!' The Prophet (peace and blessings be upon him) asked, 'What is that condition you want to stipulate?' 'It is that all my past sins be forgiven,' I said. The Prophet (peace and blessings be upon him) said: 'O `Amr! Do you not know that embracing Islam removes all the sins committed before it; that Hijrah (migration in Allah's Cause) wipes off all sins; and that performing Hajj blots out all one's past sins!"' (Saheeh Muslim)