Best solution for Wireless Sensor Network

Projects General Guidance
1

Hi, I need a board with a really low power MCU, a plug/charger for a LIPO battery and the xBee socket.
I need to run my board for 3-4 months reading each minute temperature and humidity.
I've seen the Arduino Pro or Arduino Fio.

  1. Is a Real Time Clock circuit necessary for the deep sleep operation mode ?
  2. Could I also use normal AA batteries ?
  3. Is there a specific ZigBee module I can use to save power ?
    I'm sorry for all these questions.
    Thanks in advance.
2

The real time clock is needed unless you have some way to trigger an interrupt. So, if you have something to generate a pulse every minute, then an RTC is not needed.
There are some nice lipo charger boards here:

You can also use this battery indicator kit to check if the battery voltage is too low: