Though the SunTimes is reporting that U2's Soldier Field tickets are sold out (at least they hipped me to the fact that a second U2 Solider Field show was just added for Sept. 13, 2009 -- those go on sale April 6, 2009), I was just able to find U2 tickets here on Ticketmaster.com, by searching for U2, clicking on the Soldier Field Chicago concert date "find tickets" link and I put in 1 ticket in the drop-down menu and got this today, Monday, March 30, 2009:
U2 360º Tour
Soldier Field, Chicago, IL
Sat, Sep 12, 2009 07:00 PM
Your Ticket(s)
Section
Row
Seats
Description
307
11
1
Price Level 1
Level 300 Seats
Reserved Seating
Type
1 Standard Admission - Select GA / Reserved Below
Ticket Price
US $250.00
Convenience Charge
US $14.95
Building Facility Charge
US $2.00
So there are U2 tickets still available there, as of this writing, and in their "Red Zone" area on Ticketmaster.com, which you can find after searching for U2's page and clicking on the "auction" link at the bottom right-side of their page.
1 (RED) Zone Backstage Tour Experience
US $1,515.00 Winning Not winning
2 (RED) Zone Experience
US $265.00
[...] March 30, 2009 Update: U2 Chicago Soldier Field tickets are still available, and they’ve added a second Chicago U2 show… [...]