Adam Rittenberg's Big10 Blog on ESPN.com had a good post about Nebraska and the Big 10, and he showed Iowa's record against the Big Red (12-26-3, btw). http://espn.go.com/blog/bigten/post/_/id/13189/nebraska-vs-the-big-ten
If we count all 41 games, the average margin of a Iowa/Nebraska game is 15 points. The average margin of Iowa's wins are 15 points, and their losses are 16 points (approximately).
However, this counts the 10 games the two schools played BEFORE 1900 (including twice in the span of two days in 1896). The two schools played relatively regularly during the early to mid-1940s. On a side note, the two schools played only twice while the legendary Nile Kinnick played at Iowa (1937 and 38). They did not meet during his 1939 Heisman trophy winning season.
After 1946, the teams did not meet again until 1979, after which the two have played six times. Nebraska has more or less crushed the Hawks five of those times, with an average margin of victory of over 30 points. Iowa's one win came with a 3 point win (though one of Nebraska's wins was also a 3 point win).
Being in the same conference now, and most likely the same division, the two schools have an excellent chance to restart a very old tradition. Hopefully, though, the series can be a bit more exciting than they have been historically...