>Ask and ye shall receive. Here is one study that concludes voter fraud is minimal.
>
>http://www.demos.org/pubs/analysis_voter_fraud.pdf
>
>A paaaage from page 10 of the report:
>
>Voter fraud appears to be very rare in the 12 states examined in that report. Legal and news records turned up little evidence of significant fraud in these states or any indication that fraud is more than a minor problem. Interviews with state officials further confirmed this impression.
>

Lies, damn lies, statistics, studies....

I think it's a pretty big problem, especially when the races are close. Special elections are the best time to find the cheating. Here are a few links regarding voter fraud that I uncovered, and ultimately forced a state senator out of office:

http://www.memphisflyer.com/memphis/Content?oid=oid%3A16954

And in this one, they almost got it right. I found the vacant lot, called the reporter and he discovered the guy was dead...
http://www.freerepublic.com/focus/f-news/1541411/posts

Then there's the story of the senator being ousted:

http://www.nashvillepost.com/news/2006/4/19/senate_ousts_ophelia_ford

And here's another case where 13 where arrested in the mid-south area:

http://www.myeyewitnessnews.com/news/local/story.aspx?content_id=311f520e-8d30-4e82-8a80-3dc15d927c68