Have you read any posts over at the winter sowing forum?
http://forums2.gardenweb.com/forums/wtrsow/

I've grown potatoes in containers for four years. My containers range from 20 to 50 gallons. If you use containers that large or larger, there's not much danger of freezing the soil if you plant 2-4 weeks before your last frost date. There is danger that a hard frost will kill off the top growth and set you back a few weeks.

The advice in my part of Ohio is to plant potatoes around the time forsythia starts to bloom, which is in the beginning of April for me. I cover the containers if temperatures are going to drop below 30. I harvest red potatoes about 75 days after planting and russets after about 120 days after planting. If you'll follow the link below, you can see photos and learn about one grower's successful timeline.

Here is a link that might be useful: Growing container potatoes