Can you show us a picture?

Pictures here.

http://forums2.gardenweb.com/forums/load/annuals/gal0513312227610.html

The left picture appears to be poppy seedling....

The thing is last fall my siblings and I were having a rotten tomato fight in the garden, and so we spread the seeds around, and so I think the ones on the left could also be tomato seedlings...don't think I'll be having tomato fights this year...

I just went outside and looked at my seedlings to compare to your pictures.
Papaver rhoeas seedlings' cotyledons look like tomato, but much smaller. Then they get a more rounded-shaped leaf. If the picture on the left is the size of a tomato seedling, than it's not a poppy. The picture on the right has cotyledons that are too rounded to be P. rhoeas...those seedlings look like a weed that first showed up in my yard from bird seed mix...hemp-nettle. Now I'm always trying to get them before they get larger, but always miss a few, and they reseed like crazy. However, it might be something other than nettle, so don't pull it until you get positive ID!

Here is a link that might be useful: hemp-nettle

Thanks for all your help everyone. I guess I'll just wait and see a few days to distinguish poppies from tomatoes. And I guess next year-no tomatoes fights! :)
And I do agree that the ones on the right are weeds, so I will take care of them as soon as possible!