So there's like, this thing going around where the zodiac has purportedly been revised. I don't put stock in it, myself (and there are people who only put stock in the one that's been used all this time), but I figured it might be interesting to see the alternate signs of the characters whose birthdays are listed.

Capricorn
Jan 25 - Sakuraba-sensei* (listed as Aquarius)
Feb 3 - Kou** (listed as Aquarius)
Feb 8 - Kuroi-sensei (listed as Aquarius)
Feb 14 - Akira
Aquarius
Mar 6 - Takara-san (Yukari) (listed as Pisces)
Pisces
Apr 16 - Patricia (listed as Aries)
Taurus
May 24 - Hiyori (listed as Gemini)
May 28 - Konata (listed as Gemini)
Gemini
Jul 7 - Kagami & Tsukasa (listed as Cancer)
Gemini/Cancer
Jul 20 - Misao (listed as Cancer)
Leo
Aug 21 - Izumi-san (Soujirou) (no change)
Sep 12 - Minami (listed as Virgo)
Virgo
Sep 17 - Fuyuki Amahara (no change)
Oct 7 - Yui (listed as Libra)
Oct 25 - Miyuki (listed as Scorpio)
Libra
Nov 4 - Ayano (listed as Scorpio)
Sagittarius
Dec 20 - Yutaka (no change)

*If you're wondering, "Who?" well, it's because she gets one appearance in the anime (introducing Akira and Minoru), and isn't named then. She has a lot more appearances in the manga.
** Similarly, she has NO appearances in the anime, but we see her from time to time in the manga.
*** Health Office Chief. Also never shows up in the anime.