Ken Timmerman has written this piece for Newsmax (which has recently been picked up by Rush Limbaugh). The allegation is that the under $200 donations that the Obama campaign does not have to itemize under FEC rules is coming from foreign donations.
I have been hearing these rumors for months and seen absolutely no substantiation. The Obama campaign is also subject to audit from the FEC, and my sense of the operation is that they have been extremely careful (in light of the earlier Norman Hsu scandal involving the Hillary Clinton campaign) to check the qualifications of all of their donors. UPDATE AND CORRECTION: The audit rules apply only to publicly financed campaigns, which Obama is not part of. But I still have seen no credible evidence to support these charges and I have heard from numerous sources about the steps the Obama campaign has taken to prevent this kind of thing from happening. And the bad p.r. alone is reason to expect that the campaign would act with great care to prevent this from happening.