1) The Beracha one recites when putting on a Talit should be pronounced, "…Asher Kideshanu Be’Mitzvotav Ve’Tzivanu Le’hit’atef Bi’tzitzit," as opposed to the incorrect pronunciation "BA’tzitzit," which appears in some books. There is a grammatical difference between the prefixes "Bi" and "Ba." When a Patah (AH sounding vowel) is used, it is in order to take place of the letter Hei. And so the word "Ba’tzitzit" is really the word "Be’ha’tzitzit", which means ‘in THE Tzitzit.’ "THE Tzitzit" refers to the Tzitzit worn in days of old, when it included the Techelet (a string dyed in a special blue pigment. The tradition identifying this dye has since been lost, and we therefore wear Tzitzit without Techelet. Hence, it is incorrect to say "THE Tzitzit," since we do not wear the special Tzitzit with the Techelet. One should therefore ensure to pronounce the word "Bi’tzitzit," rather than "Ba’tzitzit."
2) The question was asked regarding a situation where several people are praying together and come to put on their Talit at about the same time. Is it permissible for one person to recite the Beracha on behalf of the others, who will answer Amen, and then immediately perform the Atifah (the wrapping of the Talit around oneself)?
The answer is that not only is this practice permissible, it is probably even preferable. There is a concept in Halacha of "Be’rov Am Hadrat Melech", that it is more appropriate to perform Mitzvot collectively, with many people together. The reason why this is not commonly done today is that this practice lends itself to a number of potential problems. First, the one reciting the Beracha may not have in mind to fulfill the obligation on behalf of the others. Second, the listeners may not have in mind to fulfill their obligation by listening. Third, if there are many people in the room, some might not hear the Beracha properly. But although practically this is generally not done, however in principle, it is proper for one person to recite the Beracha over the Talit on behalf of others. Maran in fact mentions this option in Shulchan Aruch.
Therefore, those who wish to, may conduct a collective recitation of the Beracha over the Talit, with one person reciting the Beracha on behalf of the others, who then answer Amen.