Here is what GOP U.S. Senate nominee Mark Kirk told the Illinois Education Association in a speech this spring:

“[A]s a former nursery school and middle school teacher, I know some of what it takes to bring order to class.”

And here is what Kirk campaign spokesperson Kristin Kukowski told the New York Times when they began looking into his teaching claims:

“Like many Americans, Mark Kirk worked during college to help pay for school,” Ms. Kukowski said. “One of his jobs was a nursery school teacher with the responsibilities one would expect.”

But the Times subsequently talked to Sally Grubb, the woman who leads the nursery school program at the church in Ithaca, N.Y where Kirk fulfilled work-study requirements during his final year as an undergrad at Cornell University.  She said that Kirk's responsibilities couldn't be described as those of a "teacher":

“He was never, ever considered a teacher,” Ms. Grubb said in an interview after researching the history of Mr. Kirk’s association with the nursery school for two days. “He was just an additional pair of hands to help a primary teaching person.” [...]

Ms. Grubb said she spoke to the teacher who led what was then a “play group” organized by parents that met in the church basement. The teacher had a “vague recollection” of having Mr. Kirk as a work study student, but she did not remember his name. She added that Mr. Kirk did not have any major responsibilities at the play group, such as creating lesson plans, and he was only an assistant who played with the children.

Kirk's statements about his other educational stint -- a year spent teaching at a private middle school in London -- have also come under scrutiny.  From the original Times article:

In a speech on the House floor on Sept. 19, 2006, as he talked about school safety, Mr. Kirk spoke about “the kids who were the brightest lights of our country’s future, and I also remember those who bore scrutiny as people who might bring a gun to class.”

The Kirk campaign has clarified that the students who "bore scrutiny as people who might bring a gun to class" were the ones he taught in England.  But Capitol Fax's Rich Miller points out the problem there:

That was a high-class private school in a hoity-toity London neighborhood. There’s just no fathomable way that people were concerned about kids bringing guns to that English school in the early 1980s.