There are many kitchen tools that many people keep on hand that will be helpful during the canning process; whether you choose to waterbath or pressure can (and by no means is this list exhaustive, this is just to help get you started out):
Kitchen Timer - a very important little tool for the kitchen in general. It helps to keep track of cooking and processing times.
Kitchen Knives - you will definitely need these for slicing, dicing, peeling, and coring!
Long-Handled Spoons - good for stirring and moving food into jars.
Saucepans - these are good for foods that need to be precooked, blanched, etc. before canning.
Measuring Cups - now the thing that you will be using these for is... *drumroll please*... MEASURING!
Measuring Spoons - ^ see above ^
Colander - great for straining, draining, liquid off of solid foods.
Ladle - use these to get things from the pot into the canning jar.
Kitchen Towel - good for cleaning up spills or using to set your canning jars on while they are cooling.
More Canning Tools.