Pumpkin is tricky - you have to scoop out the "guts" and separate, then wash the seeds. I thought you had to "ferment" the seeds to get the guck off but SSE doesn't say that.
http://www.seedsavers.org/site... (specific instructions for different crops.)
Melons (I guess including pumpkin) : To avoid cross-pollination, isolate ΒΌ mile from watermelons, cantaloupes, muskmelons, honeydew, snake melon, and Armenian cucumbers). Save seeds from early ripening melons. Wash seeds from ripe melons in a strainer and dry. Seeds are ready to store when they break instead of bend.
Here are some links to how-to-save various kinds of seeds :
http://theseedsite.co.uk/harve...
http://www.seedsavers.org/Educ...
http://www.seedsavers.org/Educ... (brief overview)
http://blog.seedsavers.org/ass... (mature seeds crunch when you chew them)
Great PDF with lots of information:
http://seedalliance.org/index....
