The LDS Church just released an essay trying to answers questions regarding the legitimacy of the Book of Abraham. The essay avoids some major issues (such as the Facsimiles) and even contradicts itself and Joseph Smith, as can be seen from this table (take from this original post):

  Essay Elsewhere in the Essay History Canon
1 The word translation typically assumes an expert knowledge of multiple languages. Joseph Smith claimed no expertise in any language. After Joseph Smith examined the papyri and commenced “the translation of some of the characters or hieroglyphics,” his history recounts, “much to our joy [we] found that one of the rolls contained the writings of Abraham.” They cut the quote just short of “a more full account of which will appear in its place, as I proceed to examine or unfold them.” (vol 2 p236) As Mr. Chandler had been told I could translate them, he brought me some of the characters, and I gave him the interpretation, and like a gentleman, he gave me the following certificate… This is to make known to all who may be desirous, concerning the knowledge of Mr. Joseph Smith, Jun., in deciphering the ancient Egyptian hieroglyphic characters..-Documented history: Vol 2, p 235 “A Translation of some ancient Records that have fallen into our hands from the catacombs of Egypt. The writings of Abraham while he was in Egypt, called the Book of Abraham, written by his own hand, upon papyrus.”
2 Alternatively, Joseph’s study of the papyri may have led to a revelation about key events and teachings in the life of Abraham, much as he had earlier received a revelation about the life of Moses while studying the Bible. See above See above See above
3 According to this view, Joseph’s translation was not a literal rendering of the papyri as a conventional translation would be. See above See above See above
4 Rather, the physical artifacts provided an occasion for meditation, reflection, and revelation. See above See above See above
5 In these inspired translations, Joseph Smith did not claim to know the ancient languages of the records he was translating. The book originated with Egyptian papyri that Joseph Smith translated beginning in 1835 October 1.—This afternoon I labored on the Egyptian alphabet, in company with Brothers Oliver Cowdery and W. W. Phelps, and during the research, the principles of astronomy as understood by Father Abraham and the ancients unfolded to our understanding, the particulars of which will appear hereafter.-Vol 2. p 236  
6 Many people saw the papyri, but no eyewitness account of the translation survives, making it impossible to reconstruct the process His journal next speaks of translating the papyri in the spring of 1842 See above  
7 They catalyzed a process whereby God gave to Joseph Smith a revelation about the life of Abraham, even if that revelation did not directly correlate to the characters on the papyri Some evidence suggests that Joseph studied the characters on the Egyptian papyri and attempted to learn the Egyptian language. His history reports that, in July 1835, he was “continually engaged in translating an alphabet to the Book of Abraham, and arrangeing a grammar of the Egyptian language as practiced by the ancients.” see above, and note that they cut the quote right before he said he was doing this for an entire month – vol 2, p235  
8 Neither the Lord nor Joseph Smith explained the process of translation of the book of Abraham, See above see above  
9 The relationship between those fragments and the text we have today is largely a matter of conjecture. See above see above 12 And it came to pass that the priests laid violence upon me, that they might slay me also, as they did those virgins upon this altar; and that you may have a knowledge of this altar, I will refer you to the representation at the commencement of this record.-Book of Abraham 1:12
10 But this claim rests on the assumption that a vignette and its adjacent text must be associated in meaning.     See above
11 The book of Abraham’s status as scripture ultimately rests on faith in the saving truths found within the book itself as witnessed by the Holy Ghost. The Book of Abraham…was canonized as part of the Pearl of Great Price in 1880.    
12 Further, Abraham 3:22–23 is written in a poetic structure more characteristic of Near Eastern languages than early American writing style. Much like the Book of Mormon, Joseph’s translation of the book of Abraham was recorded in the language of the King James Bible.    
13 Some of these extra-biblical elements were available in apocryphal books or biblical commentaries in Joseph Smith’s lifetime   Revelation given through Joseph Smith the Prophet, at Kirtland, Ohio, March 9, 1833. The Prophet was at this time engaged in the translation of the Old Testament. Having come to that portion of the ancient writings called the Apocrypha, he inquired of the Lord and received this instruction. – D&C 91  

MormonThink has a more complete overview of problems with the Book of Abraham.