Other Sexing baby hammies

I'm fostering a litter of baby hamsters for the spca and will need to seperate them by sex in a few weeks. Does anyone know of any reliable websites (preferably with pictures) for sexing the babies?

Also, any tips on socializing the momma hamster? I've been able to handle her without problems but she is being very nippy with the other members of my family, despite trying to be careful and gentle with her.

Thanks