Not to disagree with the other answers to your post, but I wanted to give my perspective.
Several of those Muslims on this board that I most respect have at times spoken of what they understand the afterlife to be like. That first there is a time of judgment.
Yes, this is a fundamental belief of Islam.
Now in many ways this sounds similar to Christian descriptions, so I want to be sure that I don't read these comments through my Christian eyes but understand them as Muslims do. Thus I am going to restate what I understand is the "typical" or "expected" experience. If I get it wrong, please correct me. But, don't attack me for having it wrong, that's why I'm asking the question.
OK
What I understand happens is that a Muslim dies and then is led before Allah who needs to be sure that no impurities enter into Paradise with him.
No, this is a Christian belief of God not being in the presence of sin. The concept of a pruification by fire (in Hell) or atonement by blood (Jesus on cross) is not an Islamic belief. Allah will show mercy to the believers and forgive many sins straight away.
That person is then actually sent to hell to be purified of any remaining sin that might be in him. Once so purified, then and only then, may he be admitted to Paradise. As to how long one must withstand this purification, it totally depends on how one has lived.
No, this implies that ALL Muslims will spend at least some time in Hell to "purify" them of any sins. This is incorrect. We believe that only the most sinful Muslim guilty, for example, of murder or adultery may be sent to Hell - or Allah may forgive even that.
Those who truly lived Islamic lives and total submission will only have to be purified a little (of what I don't know if they lived totally submissive lives).
No, we believe these will not spend any time in Hellfire.
Those who claimed to belong to Allah but did not live very submissive lives might be there a long time.
Another way of saying that they lived sinful lives, as in did not worship Allah as instructed and/or who commited grievous cimes. Yes, they may need to be in the Hellfire for considerable time.
And those who have knowingly rejected Allah by worshipping other gods in the place of Allah or associating partners with Allah won't even have the opportunity to be purified, we are just dam*ed.
The judging is for Allah to do, but according to my understanding of the Quran, I would not want to die in that state.
I have the CD set "Journey to the Hereafter" that gives an overview of the Islamic point of view:
http://www.soundvision.com/shop/pview.asp?item=710-017
From my understanding and from what I remember from these Cds, a person's judgement is in stages.
1) questioning in the grave determining ease or torment until the Day of Judgement
2) receiving one's life history book in his right hand (good) or from behind his back in his left hand (bad)
3) balance of good and bad deeds with the heaviest good deed = testimony that there is no god worthy of worship but Allah. The balance is divinely Just and no one can question or appeal to a higher court.
4) passing across the razor thin bridge over Hell. The most pious will pass quickly in the twinkling of an eye, some will run, some will walk and some will crawl. The quicker one can cross the bridge, the less likely he will fall into Hellfire.
During these last 3 stages, everyone will be so concerned for his own state that he will forget about everyone else he/she knew on earth. Most Muslims will pass directly to Paradise, but those with an equal balance of good and bad will go to the "Heights" between Paradise and Hell while the most sinful will go to the Hellfire. If one died believing there is One God with no partners, no father, no mother, no son and no daughter, then eventually he will be brought out of the Heights or Hellfire. Another thing to remember is that Allah's Mercy is still the critical element and no Muslim is so arrogant as to say he has lived such a life and prayed so perfectly that he is guaranteed a place in Paradise. We have a sublime balance of fear of Allah's Wrath and hope in His Mercy.
..and Allah knows best. Those more knowledgeable than me will kindly correct my errors.