Agree with everything schmave says. You'll find a warm welcome over at DX and reception.
So, I'm a little late to the party, but here's what I can hear (or have heard on occasion) from Iowa at my location about 44 miles northwest of downtown Chicago....
540: KWMT, Fort Dodge. Daytime, under WAUK from the Milwaukee area. Nulling WAUK can produce a listenable KWMT.
600: WMT, Cedar Rapids. Reliable daytime signal. Still present at night, but often gets swallowed up by other signals.
640: WOI, Ames. Very weak, but audible under WMFN (Grand Rapids, MI area) daytime. Stronger, but not always dominant at night
800: KXIC, Iowa City. Very weak, but audible daytime on a good radio. Sometimes mixing with CKLW (Detroit/Windsor)
910: WSUI, Iowa City. A little stronger than KXIC during daytime, but not by much. Disappears at night
940: KPSZ, Des Moines. In it's days as KIOA, it could be an occasional visitor around sunset before going to night pattern and power
1040: WHO, Des Moines. I used to be just out of range of their day signal. Generally a good signal at night. Local pest on 1030 doesn't help matters
1170: KJOC, Davenport. Occasional nighttime visitor
1300: KGLO, Mason City. Sometimes audible around sunset before going to night pattern
1420: WOC, Davenport. I'm just beyond their max day range, but once in a while thy turn up at night
1460: KXNO, Des Moines. "Back in the day" as KSO, they were reliable here at night. As KXNO, not so much, but they still turn up once in a while.
1540: KXEL, Waterloo. Monster night signal here. Strongest Iowa Signal by a significant degree
1600: KCRG, Cedar Rapids. I think the call letters have changed, but as KCRG this was a fairly easy night time catch
Finally, there are three x-banders. 1630, 1650, and 1700. Iowa City, Cedar Falls, and Des Moines, respectively. 1630 is KCJJ (Run by the legendary "Captain Steve" Bridges...who I once just missed being on the same staff with). The other two stations have changed calls once or twice. All have fairly reliable night signals here, with KCJJ usually being just a tad better than the other two.