Easter is celebrated to varying degrees in the Islamic world, ranging from outright illegal in Saudi Arabia to being openly celebrated in some of the Gulf States and the Far East. A natural question is, just where does Islam diverge from Christianity on the matter of Jesus' AS1 crucifixion and resurrection? The Qur'an says,
[4:157] That they said (in boast), "We killed Christ Jesus the son of Mary, the Messenger of Allah";- but they killed him not, nor crucified him, but so it was made to appear to them, and those who differ therein are full of doubts, with no (certain) knowledge, but only conjecture to follow, for of a surety they killed him not
[4:158] Nay, Allah raised him up unto Himself; and Allah is Exalted in Power, Wise
[4:159] And there is none of the People of the Book but must believe in him before his death; and on the Day of Judgment he will be a witness against them
Here, the Qur'an states clearly that Jesus AS was not killed nor crucified, but was indeed raised to Heaven. Therefore, Easter has no direct analogue in Islam since it is the celebration of his resurrection. However, as the third verse above explains, Jesus will also play a role on Judgement Day.
There is, of course, some historical evidence that supports the crucifixion as a recorded event, including from some Roman sources. And the verse in the Qur'an itself says quite explicitly that "so it was made to appear to them". So it seems plausible that someone was crucified, unless it was all a divine illusion. One of the mainstream views among Muslim theologians is that another was crucified in Jesus' AS place; either as punishment (likely Judas) or as a willing martyr (often cited as Simon). There are also various minority views, in which Jesus AS did die or achieved separation of the spirit from his body. The Wikipedia article "Islamic views of Jesus' death" provides a comprehensive overview of the various interpretations.
So, as in so many other things, Islam and Christianity do indeed differ but also agree in important ways. As far as both faiths are concerned, Jesus AS did ascend to Heaven. Literally, Christ is risen. As far as Jesus' AS return, we can differ on when, but the key is that the return itself is agreed upon. What better sign of God's love for his Creation?
And it should be noted that any Muslim claiming that Easter is un-Islamic is quite wrong. There's enough to celebrate about Jesus's AS ascension to Heaven for Muslims as for Christians on this day.
1 The acronym AS appended to Jesus' AS name is short for "alayhis salaam" which translates as "blessings upon him".