agree with u 100 % ere Das .. and as some are confused .. the Wives if the Holy Prophet SAW are also considered part of the Ahl e Bayt.
however, i wud like to point one thing out that any family from the Prophet SAW from the banu Quraish are also considered of Ahl e Beyt .. But keeping in mind that the Lineage of Saadaat i.e. Sayed's is only continuous from the family of Hazrat Ali RA and Ummul Mu mineen Seyeda Fatimah RA. And those whose lineage goes and is linked to the Quraish Tribe are not Seyed's although still prt of the Ahl e Beyt .. :)
First of all I'd like to point out that Sayyeda Fatima Zahra (sa) is NOT Ummul Momineen. Only the wives of the Prophet (saw) are. Fatima Zahra (sa) is Sayyedatul Nisa-el-Alameen which is in your books, but is another story so lets stay on topic.
The Ahl-ul-Bayt/Panjtaan Paak were identified during the events Kisa and Mubahila. Hadees-e-Kisa was posted above and it was narrated by Aisha herself. Was she under the cloak? I'm pretty sure you are aware of the event of Mubahila, where were the wives there? yes, they are the wives of the Prophet (saw), they are ALL Ummul Momineen but they are not of the Ahl-ul-Bayt.
Surah 33, Ayah 33 also makes it clear, read that and then read Surah Tahreem and decide whether the wives of Rasoolallah (saw) are part of Ahl-ul-Bayt or not.