It is well known that Moshe's name does not appear in this week's Parsha. This omission is usually attributed to Moshe's prayer to Hashem in which he asked Hashem to please forgive the sin of Bnai Yisrael (after they worshipped the Golden Calf) and if not, to please erase his name out of the book which Hashem has written (שמות ל"ב:ל"ב). Assuming that "the book" referred to the Torah, many learn that Moshe was asking to be removed from the Torah; Hashem complied in part by leaving his name out of this Parsha.
But why of all the Parshiyos was his name eliminated specifically from Parshas Tetzaveh? Some say that the reason is that the anniversary of Moshe's death, the seventh of Adar, generally occurs during the week which we read Parshas Tetzaveh, and death symbolizes elimination. Indeed, some say that "the book" referred to is the book of life; Moshe was thus asking to be taken from this world and we note this by omitting his name from the Parsha read during the week of his Yahrzeit.
Regardless of this, it can indeed be said that Moshe's name does in fact appear in our Parsha, albeit in a hidden manner. The Vilna Gaon explains that every letter of the Aleph-Bais has within it a concealed part and a revealed part. For example, the letter "ב" is written out as בית"" the "ב" being the revealed part, and the "י" and the ת"" being the concealed part. With this, we can understand how Moshe's name is in the Parsha, which consists of one hundred and one Pesukim. If we look at the concealed parts of the letters which spell the name משה we find that the concealed part of the letter מ"", spelled out as מם"", which is also "מ", equals forty, the concealed part of the letter "ש", spelled out as שין"", is a י"" and a "ן", which together equal sixty, and the concealed part of the letter "ה", spelled out as הא"" is an "א" which equals one. The sum total of the concealed parts of the letters spelling משה is one hundred and one, the exact same number of verses in this Parsha. Moshe's name concealed in our Parsha in such a fashion is further proof that one should never take things at face value, for things aren't always as plain as they seem.