Bicycle Tutor

My rear wheel wobbles subtly to the left and right, causing the tire to rub against the frame of the bike. I've got a couple of pictures here of the tire resting against the frame, and then me placing my finger in between them, to illustrate the wobble. Any advice?
Thanks so much!
Ford

Oops! Sorry for the double-thread, and here are the pictures. Thanks again!

   
   

Hi Fjord,
Lemme take a shot at this(bear with me lol). First when you say "wobble" do you mean when the wheel is in motion? First try to move the wheel (wiggle) side to side with you hand to see if theres any movement that way. Next if you are talking about when the wheel is in motion then the wheel needs to be trued heres Alex's video on wheel truing:
http://bicycletutor.com/wheel-truing/
For faint of heart, lol, if anyone else would like to add please do so.

Well, the wheel has lateral play at any time. In the pictures I took here, the bike was resting upside-down, and the tire can be moved left and right. The gears move right along with the tire, so everything between the "fork" frame around the back tire is free to move at any time. Thanks for your help Bill - I would be lost on my own.

- the hub needs to be checked and adjusted http://bicycletutor.com/overhaul-wheel-bearings/ though it is probably shot
- or maybe the wheel is not fixed in the frame