SIRLEI - Are there any other other references to Christ's birthday being April 6th other than the inference in D&C 20:1? I noticed that even in Mormon Doctrine McConkie states "apparently" he was born on April 6th.

JOEL -
"The rise of the Church of Christ in these last days, being one thousand eight hundred and thirty years since the coming of our Lord and Savior Jesus Christ in the flesh," (D&C 20:1)

Some argue that the phrase "one thousand eight hundred and thirty years since the coming of our Lord and Savior Jesus Christ in the flesh", should be interpreted to mean that Christ was born exactly on April 6, 1830 years ago. Others believe that the phrase was not intended to fix the year of Christ's birth but was simply an oratorical mode of expressing the current year. I tend to agree with the latter, although there are other reasons for setting the date for Christ's birth on or close to April 6.
Bruce R. McConkie also stated in his "Mortal Messiah":

"We do not believe it is possible with the present state of our knowledge-including that which is known both in and out of the Church-to state with finality when the natal day of the Lord Jesus actually occurred" (McConkie, Bruce R. Mortal Messiah, Vol. 1, p. 349, n. 2. Salt Lake City, 1979).

There are no records of Joseph Smith confirming that April 6 is the birth date of Jesus and the Church has no official position on this matter. However, presidents of the Church, including Harold B. Lee(1973) and Spencer W. Kimball(1980), have offered opinions that April 6 is the true anniversary of Christ's birth. But other than the D&C 20 verse there are no other scriptural references that directly support the April 6 date.
Many Bible scholars agree that Jesus may have been born sometime in the Spring. The fact that ‘there was no room for them in the inn’ (Luke 2:7) suggests that the birth probably occurred at the time of one of the three feasts, such as Passover, at which Jews were required to be in Jerusalem. The time of the Passover at the year 1 BC just happens to fall on or about April 6.
Interesting to note that many other important events occured during the time of Passover:

1. Christ possibly born on this date.
2. Jesus began to perform miracles openly, marking the beginning of his public ministry. (John 2:23)
3. The Savior cleansed the temple just before Passover both at the beginning of his ministry (see John 2:13–16) and at the end (see Matt. 21:12–13)
4. Jesus instituted the Sacrament and was sacrificed and resurrected at Passover time(Matt. 26:26-28)
5. The Church was organized on April 6
6. Oliver Cowdery began his duties as scribe for the Book of Mormon on April 7.
7. Jesus, Moses, Elias, and Elijah appeared to Joseph Smith and Oliver Cowdery in the Kirtland Temple on April 3, 1836.
8. Brigham Young dedicated the completed St. George Temple on April 6, 1877.
9. The Salt Lake Temple was dedicated April 6 1893.

A good article on this is found in the January 1994 Ensign:
John P. Pratt, “Passover—Was It Symbolic of His Coming?” Ensign, Jan. 1994, 38

References:
Kimball, Spencer W. "Remarks and Dedication of the Fayette, New York, Buildings." Ensign 10 (May 1980):54.
Lee, Harold B. "Strengthening the Stakes of Zion." Ensign 3 (July 1973):2