Must women hear the reading of Parshas Zachor?
It is a Biblical obligation to hear Parshas Zachor. Some Poskim rule women are not obligated to hear Parshas Zachor. Other Poskim rule they are obligated just like men. Practically the custom amongst many women is to treat the reading as an obligation.
May one make a separate Minyan of Zachor for women?
Some communities have the custom to make a separate Minyan for women to hear Parshas Zachor [without a blessing]. However, some Poskim argue that it should not be done.
 Michaber 146/2; 685/7; Admur 282/16; Tosafus; Rashba; Rosh [Brachos 13a]; Hagahos Ashriy Chapter 6 Brachos; Tosafus Shantz brought in Terumas Hadeshen 8; Smak; based on Megillah 18a.; See M”A 685/1; Shaareiy Halacha Uminhag 2/287; Some opinions rule this Biblical obligation is only fulfilled if one hears the reading of Zachor from a Sefer Torah together with a Minyan. [Mahram Shick Mitzvah 605] Others rule the Biblical obligation is fulfilled by simply mentioning the remembrance of Amalek, and hearing it from the Torah with a Minyan is only Rabbinical. [Chinuch 603; Ramban Ki Seitzei; Toras Chesed [Lublin] 37] According to all, the Biblical obligation is fulfilled whenever one hears the reading of Amalek from the Torah, such as on Parshas Ki Seitzei and, according to some Poskim, also on Parshas Bishalach. [M”A 685/1] Nevertheless, Rabbinically one must initially fulfill this Biblical obligation with the reading on Parshas Zachor. [Aruch Hashulchan ibid]
The source: This is learned from the verse “Zachor Es Asher Asa Lecha Amaleik” which implies one must verbalize the remembrance of Amaleik and it does not suffice to remember it in one’s mind. [Kaf Hachaim 685/33]
 Chinuch 603; Avnei Nezer 509; Marcheshes 1/22; Aruch Hashulchan 685/2; Arugas Habosem 205; Tzitz Hakodesh 1/51; Hisorerus Teshuvah 1/5; Divreiy Chaim 2/14; Kaf Hachaim 685/30; Toras Chesed [Lublin] 37: “Minhag Yisrael is Torah and we have never heard of women going to Shul for Parshas Zachor. One should not be Machmir in this”
 The reason: As a) Women are not obligated in the Mitzvah to remember Amaleik. [Chinuch ibid] b) Even if women are obligated, the Biblical command is just to remember, while the hearing from a Sefer Torah with a Minyan is only Rabbinical, and was only established for men. [Toras Chesed ibid]
 Minchas Chinuch Mitzvah 603, Binyan Tziyon 2:8 in name of Rav Nassan Adler; Minchas Elazar 2/1-5; Darkei Chaim Veshalom 835; and other Poskim mentioned in Sdei Chemed Klalim Mareches Zayin Klal 13; Minchas Yitzchak 9/68
 The reason: As women are obligated in the Mitzvah of remembering Amaleik, as it is not a time dependent positive command [see Toras Chesed ibid] and thus they receive the same laws as the men in this regard.
 Minchas Yitzchak 9/68
 Minchas Yitzchak 9/68
 Toras Chesed [Lublin] 37; Mikraeiy kodesh; Kinyan Torah 7:53; Shraga Hameir 6/16; Poskim brought in Minchas Yitzchak ibid
 The reason: As one should not remove a Torah from the ark for a reading which is not obligatory. [ibid]