Okay, so the garden is in place and you have more tomatoes than you can eat? You can share them w/ neighbors or donate to a soup kitchen. You still have some left? Well, canning or freezing is one way to preserve some of your fruits and vegetables. The National Center for Food Preservation provides some useful information to get you started.
Their website: http://www.uga.edu/nchfp/how/can_home.html