On "Shabbat Zachor," the Shabbat before Purim, we take two Torah scrolls from the Heichal. After reading the regular Torah portion from the first Torah, we open the second scroll and read for the Maftir reading the final verses of Parashat Ki-Teitzei (Devarim 25:17-19) which command us to recount Amalek's attack on Benei Yisrael. According to many Halachic authorities, including the Shulchan Aruch, the annual reading of these verses constitutes a Torah obligation. The Zachor reading differs in this regard from the standard Torah reading, in that it is a Torah obligation.
In light of the unique status of the Zachor reading, is it proper for the congregation to read along with the Ba'al Koreh (reader) from their Chumashim as he reads Zachor?
Although some Rabbis indeed encouraged reading Zachor along with the Ba'al Koreh, Chacham Ovadia Yosef, in his work Chazon Ovadia (Laws of Purim, p. 4), rules that to the contrary, this practice is inappropriate. Firstly, he notes that the Torah introduces the obligation to recall Amalek's assault with the term "Zachor" (literally, "Remember") – the same term with which the Torah introduces the obligation of Kiddush on Shabbat (Shemot 20:8). The Sages understood the word "Zachor" as a reference to verbal recitation, thus requiring that one verbally declare the sanctity of Shabbat every Shabbat, and verbally recall the incident of Amalek once a year. As we know, one can fulfill his obligation of Kiddush by listening to its recitation from somebody else. The Halachic principle of "Shomei'a Ke'oneh" establishes that by carefully listening to somebody else's recitation, one is considered to have personally recited the given text. Therefore, one is not required to personally recite Kiddush on Shabbat, and it suffices for him to listen to its recitation by another person. Similarly, the obligation to read the Zachor section can be fulfilled by listening to the reader, and there is thus no need for the congregation to read the verses of Zachor along with the Ba'al Koreh, as they satisfy their obligation by carefully listening to his reading.
Furthermore, Chacham Ovadia adds, the Zachor obligation requires reading this section from a proper Torah scroll. Therefore, the congregation can fulfill their obligation only by listening to the Ba'al Koreh's reading, whereby they are considered to have themselves read the Zachor section from a Torah scroll. If they read from their Chumashim, then they do not fulfill their obligation. It is therefore appropriate for the congregation to remain perfectly silent during the Zachor reading and carefully listen to each word read by the Ba'al Koreh.
There is some discussion among the Halachic authorities as to whether or not women are included in the obligation to hear the Zachor reading, and therefore many women indeed make a point to come to the synagogue on Shabbat Zachor to hear this reading. Many communities conduct a special Zachor reading on the afternoon of Shabbat Zachor for women who are unable to attend synagogue services in the morning. Some Rabbis discouraged this practice, arguing that it is inappropriate to take the Torah scroll from the Heichal for this reading, since no Beracha is recited over this reading and it is unclear whether or not it is in fact required. Chacham Ovadia Yosef, however (In Chazon Ovadia – Laws of Purim, p. 10), encourages this practice, claiming that reading the Zachor section for women is indeed a worthy enough purpose to warrant removing the Torah from the Heichal. He draws proof to his position from the practice of Rabbi Moshe Greenwald (early 20th-century author of the "Arugat Ha'bosem") to remove the Torah from the Heichal each morning during the first twelve days of Nissan and read from the section of the "Nesi'im" in the Book of Bamidbar (7:1-8:4). Even though reading from the "Nesi'im" section during this period is not required by Halacha, and is merely a Minhag (custom), this practice is deemed worthwhile enough to allow removing the Torah from the Heichal. Certainly, then, it is proper to conduct a special Zachor reading for women in deference to the view among the authorities that the Zachor obligation applies to both men and women.
Why is no Beracha recited over the Mitzva of reading Zachor? Many Mitzvot that we perform require the recitation of a Beracha. Seemingly, then, before the Zachor reading we should recite the Beracha "Asher Kideshanu Be'mitzvotav Ve'tzivanu Li'zkor Ma'aseh Amalek." Why did the Rabbis not require the recitation of a Beracha before the performance of this Mitzva?
Chacham Ovadia (Chazon Ovadia – Laws of Purim, p. 11) cites those who answer this question on the basis of the Gemara's comment in Masechet Megila (10b) that the Almighty does not rejoice in the destruction of the wicked. Although the wicked people in the world must be eliminated, their death should not be a cause of joy and celebration. Thus, for example, when the ministering angels wished to sing a song of praise upon the drowning of the Egyptians in the sea, God exclaimed, "My creatures are drowning at sea – and you wish to sing a song of praise?!" Therefore, even though we must conduct a special reading to recall the obligation to destroy Amalek, the Sages chose not to require the recitation of a Beracha, which would express a feeling of joy and excitement over the destruction of the wicked.
Summary: On the Shabbat before Purim we read for the Maftir reading the section of "Zachor" from a separate Torah scroll. The congregation should remain silent during the reading, rather than read along with the Ba'al Koreh (reader). Some authorities require women to hear this reading, as well. Many communities therefore conduct a special Zachor reading during the afternoon of Shabbat Zachor for women who cannot attend the morning services, and this is a proper practice.