This post about seeds for a cold climate on Cold Climate Gardening is just terrific. The subsequent discussion in the comments section is also well worth a read. Some great seed sources are listed, as well as things to keep in mind while shopping for seeds.
Keep in mind that heirloom seeds have been chosen and saved for generations in an area or region not just for their fantastic flavors, but because they are well-adapted to that particular climate. Local heirlooms from Project Grow are available at the 2010 Annual Seed Swap on Saturday, February 13th, and can also be found at People's Food Coop, too.
Seed Savers Exchange specializes in heirlooms, and offers lots of good information about where they come from, how they grow, and the flavors they produce.
Garden Faerie also does a fun little seed swap, but you'll have to plan on participating next year. Check out her book - Fun with Winter Seed Sowing - to get a jump start on things, too!
2010 Annual Seed Swap
Saturday, February 13th
10am - 11:30am