Buy the 2015 Old Farmer's Almanac!
Reporting is a is a fairly good site. You simply list the seeds you have and search for people that are interested in trading with you.

2015 Garden Calendar2015 Weather Watcher's Calendar2015 Recipes Calendar2015 Engagement Calendar 2015 Everyday Calendar2015 Country CalendarNew Year Cross StitchLobster Rope Doormats