I cut all of my dog's nails myself and start training them and cutting their nails the first day the come to live with me. I would have a vet or groomer show you first, after that it is really easy and alot cheaper than to have to go to the groomer's or vet's to get their nails cut.
Here are some sites that show you how to cut their nails.
This first one has great instructions and illustrations!! Oh and in case you cut the quick by accident, have quik stop or baking soda on hand to stop the bleeding right away!
http://www.vetmed.wsu.edu/ClientED/dog_nails.asp http://www.thepetcenter.com/gen/nailtrim.htm