http://hgic.clemson.edu/factsheets/HGIC3320.htm
FREEZING TOMATOES
Select firm, ripe tomatoes with deep red color.
Wash and dip in boiling water for 30 seconds to loosen skins. Core and peel. Freeze whole or in pieces. Pack into containers, leaving 1-inch headspace. Seal and freeze. Use only for cooking or seasoning, as tomatoes will not be solid when thawed.