Is there sin in heaven? After all, Satan was there.

Is there sin in Heaven?  I never thought so before, because God us holy and cannot tolerate sin. Then I read about Satan talking to God about Job...God is on heaven, so I am assuming this took place in heaven. So, how was Satan, the king of sin, talking to God? I was confused. So, I did some research. I am happy to say, it all makes sense to me now...well at least I understand that God is holy and sinless and if He wants to talk to Satan, well, Satan doesn't have a choice. 

From for questions.org
http://www.gotquestions.org/war-in-heaven.html

Question: Is the war in heaven in Revelation 12 describing Satan's original fall or an end times angelic battle?The last great angelic battle and Satan’s ultimate expulsion from heaven are described inRevelation 12:7–12. In this passage, John sees a great war between Michael and the angels of God and the dragon (Satan) and his fallen angels or demons that will take place in the end times. Satan, in his great pride and delusion that he can be like God, will lead a final rebellion against God. It will be a cosmic mismatch. Thus, the dragon and his demons will lose the battle and be thrown out of heaven forever.

A common misconception is that Satan and his demons were locked away in hell after the fall of Satan. It is clear from many Bible passages that Satan was not barred from heaven or the earth after his first rebellion, which predated the creation. In Job 1:1—2:8, he appears before God to accuse Job of ulterior motives in his worship of God. In Zechariah 3, he again appears before God to accuse Joshua, the high priest. Indeed, the name Satan means “accuser.” In Genesis, he visited the Garden of Eden and tempted Eve. He tempted Jesus in the wilderness before Jesus began His ministry, an incident recorded inMatthew 4:1–11. The question arises that, if Satan had already rebelled and been cast from heaven before the world was created, why is he free to be in heaven and on earth?

In 2 Corinthians 12:2–3, the apostle Paul provides a major revelation that there are three “heavens.” In this passage, he seemingly talks about himself being taken up to the “third heaven” where God the Father and Jesus dwell. The second heaven is the universe or outer space, and the first is our atmosphere or air. The Bible indicates that Satan and some of his demons are allowed to move in this space (Ephesians 2:1–2; 6:12).

In this age, Satan and his highest ranking angels can still oppose the work of God and hinder the angels of God (Daniel 10:10–14) within the boundaries of the middle or second heaven. The battle recorded in Revelation 12 removes Satan and his minions from this realm.

When Satan is expelled from the middle heaven, there will be great rejoicing in heaven, since the age-old accuser will be forever banned from his mission of accusation and slander against the elect. Satan’s power and freedom will be seriously curtailed. However, the inhabitants of the earth will suffer terribly after this event, because Satan will be enraged. He will also be aware that he only has three and a half more years until he is bound and cast into the bottomless pit. This will usher in a period of intensified suffering on earth (the Great Tribulation) during which the Antichrist violates his peace treaty with Israel, desecrates their temple, declares himself as god, and begins to systematically murder all those who refuse to worship him.


Also, in gotquestions.org
http://www.gotquestions.org/Satan-access.html

Question: Does Satan still have access to Heaven? Why does God allow Satan to enter Heaven, as recorded in the Bible?

Satan was originally one of God's holy angels, but he rebelled against God and was cast out of heaven (Luke 10:18). That was only the first stage of his judgment. Satan's kingdom was vanquished at the cross (John 12:31-32). Later, he will be bound in the abyss for one thousand years (Revelation 20:1-3) and then will be cast into the lake of fire for eternity (Revelation 20:10).

Until his final judgment, Satan is "the prince of this world" (John 14:30), but it seems that he still has restricted access to the heavenly realms. InJob 1:6, Satan stands in the presence of God. (See2 Chronicles 18:18-21 for a similar situation involving a "lying spirit.") 

Since God is holy and absolutely without sin (Isaiah 6:3), and since He will not even look on evil (Habakkuk 1:13), how can Satan be in heaven? The answer involves God's sovereign restraint of sin. In Job 1, Satan stood before God to give an account of himself. God initiated the meeting, led the proceedings, and remained in absolute control (verse 7). The result was that Satan's power was limited (verse 12) and God was glorified.

Here are some other facts to note: 1) Satan does not have open access to God's presence. He is summoned by God. 2) The visits are temporary. His time before God's throne is limited. 3) In no way is the purity of heaven tainted by the brief, God-ordained presence of a sinful being, "quarantined," as it were, by God's regulatory power. And, 4) Satan's access is only granted prior to the final judgment. After the judgment, God creates a new heaven and new earth (Revelation 21:1), wipes away all tears from our eyes (verse 4), reveals the New Jerusalem (verse 10), and promises the complete absence of sin (verse 27).

When we say, "God cannot allow sin into heaven," we simply mean that God cannot allow human beings who are still in their sin to live in His presence. But it is possible for God to command a sinful being to stand (temporarily) in His presence in order to commission him (Isaiah 6), to exact an account from him (Job 1-2), or to judge him (Revelation 20:11-15) without compromising His holiness.

God's holiness will eventually consume all sin. Until that day, His holiness regulates sin, and that means that Satan, on certain occasions, is briefly summoned before his Creator to give an account of his actions.