Actually, I'm not even sure if they are weeds or not. I don't know
much about horticulture. I tried a few web sites to try to id them
myself, but couldn't even answer most of the questions (ex,
http://weedid.aces.uiuc.edu/).

You can view the pics at: http://www.jokabomo.com/weeds/

Also, if they are weeds, how to I get rid of them? They seem to be
centrally located only on one part of my property. I assume good old
fashioned yanking up by the roots will work. They seem to be
strangling some wild raspberry plants and would like to try to save
the berry plants.

Thanks in advance.
John