You can receive time signal voices and various messages (wake-up call, birthday, encouraging words, love confession and such). The basic charge is 100 points/yen (roughly US$1.24) for one message.
You can also choose the type of character from:
・Tsundere older lady
・Dojikko little sister
・Cool class president
・Cheerful older sister ...and more.
The three anime voice actresses available now are:
(you can hear their sample voices in the linked profile pages)
Naru Narusegawa (Love Hina)
Tohru Honda(Fruits Basket)
Ayu Tsukimiya (Kanon)
Ritsu Tainaka (K-On!)
Wendy Marvell (FAIRY TAIL)
Amu Hinamori (Shugo Chara!)
Elucia de Lut Ima "Elsie" (The World God Only Knows)
Ruiko Saten (Toaru Kagaku no Railgun)