If you are just canning tomatoes with little or no other low acid vegetables added (onions, garlic, peppers, celery, carrots, etc.), then a boiling water bath is fine - 35 minutes for pints and 40 minutes for quarts. You should add some acid to the tomatoes to make sure the pH is below 4.6, such as citric acid (1/4 tsp/pint) or bottled lemon juice (1 TBS/pint). If you add a significant amount of other low acid vegetables, pressure canning is safer.
Complete instructions and recipes can be found here:
http://nchfp.uga.edu/how/can3_tomato.html
There are very very few cases of botulism from home canned tomatoes because they are pretty high in acid, but it is just as easy to do it right and be sure - some varieties of tomatoes are low in acid and push the limit. Surprisingly, the addition of lemon juice, or especially citric acid, does not detract from the flavor.
I canned my delicious salsa wrong for over 30 years without incident, but now I add acid and pressure can it for the added safety. I just canned 15 pints today.
TomNJ