My Introductory Hebrew class was reading Genesis 1 today, and we wrestled with the old, fun problem of whether the story begins with "in the beginning" or "when God began to..." or (most likely) "in the beginning, when..." The BHS textual apparatus makes an interesting reference to appendix II of Paul Kahle's 1959 book on text and translation, The Cairo Geniza.
This appendix gives a transliteration recorded at Nablus in 1917 by Hellmut Ritter and Arthur Schaade of how the Samaritan community was pronouncing chuncks of Genesis and Exodus. BHS understands their pronounciation of the first word of Gen 1:1 to lend support to reading "In the beginning." Below is a scan of part of p. 318 (click to enlarge). You can see that overall there are quite a few differences between Samaritan pronunciation and both standard Jewish and scientific/academic pronounciation of biblical Hebrew: