It is for the square wave out, what could be also used for alarm, but also for other things (such as for move a real-physical clock). But for the moment i have the alarms near to be working, and i don´t use the INTB/SQW (the libraries that i found there don´t use it).
I use: Vcc (3V3 OR 5V both works for me, but i prefer to use 3V3), GND, INTA (Digital pin 2 OR Digital pin 3, is up to you), SDA (analog pin 4), SCL (Analog Pin 5).
cheers,
Hi and thank you for fast reply 
but another question:
why do you use the analog pins on the RTC?
SDA and SCL
i thought this chip was all digital 
Uhmm good question. I am so noob on electronics, but i think that this is because the serial communication between ds1337 an arduino. Many other devices uses serial comunications by this way. Other communication way is the SPI through the 10 to 13 digital pins in arduino. But this device (as far as i know) don´t have this type of communications.
BUT, i used it because i readed that it must be in that way. I don´t know if other type of communucations are possible for this device, sorry :-[
[edit]Sorry, i mean analog pins 4 and 5 are for I2C communications, what (as far as i know) it the communication way for this sensor...[/edit]
I used the DS1337 following this circuit:
http://fritzing.org/projects/ds1337/
The battery used to power the ds1337 is a 3V coin-cell (not the AA cells showed in the diagram), what should remain for more than one year. However, the coin cell is already dry after about one month.
I think that the diode between the coin-cell and the ds1337 consume a lot of power, also when the RTC is connected to the arduino board.
I am not sure if i could remove this diode... may be it could be dangerous, burning the coin-cell when it is connected to the arduino board 3V3 pin... or not? Do you recommend to me to use a rechargeable 3V coin cell?
Any idea about how could i solve this problem?
Thanks a lot!!