When to pick a pumpkin

[lgxkls]

I have two pumpkin plants sprawling over my plot. They have produced several small pumpkins  (about 4-6" diameter) and also a couple of  large pumpkins (about 12-18" diameter).
I was not intending to grow giants and so wondered when the large ones will be ready to pick.
I thought that if I picked them some of the smaller ones might get bigger? Is this right.
Will the picked pumpkins store well and if so for how long.
Thanks
Karon

[Curryandchips]

From what I have gleaned, the young pumpkins are perfectly edible, but are unlikely to keep unless they are allowed to ripen naturally. I would consider that the early picked fruit should be ok for several weeks though, if kept in the dry. I agree that by removing some of the fruit, the others should grow more ...

[Squashfan]

this link below might help. I usually skip the bleach n shellac part  ;D. My pumpkins keep for months anyway. The longer they stay on the vine the better, I think. Having said that, I'm going to take off one monster I have to allow the others on the vine to grow this week. I find the dry heat thing seems to work for them. Good luck!
http://www.aces.edu/dept/extcomm/specialty/pumpkins.html

[Squashfan]

Actually, this one's a better link. Ignore the shellac. http://www.urbanext.uiuc.edu/Pumpkins/growing.html