The Eighth Circuit website is announcing new local rules effective October 1, 2010, with the following notation: "Counsel's attention is directed to [new] Rules 25A, 25B and 28A."
New Rule 25A contains a list of documents that "must be filed electronically," including briefs, but states that e-filing is "voluntary for all pro se litigants proceeding without counsel" (discussed further in new Rule 25B). Per new Rule 28A, counsel will also provide paper copies of a brief to the court and other parties, but not until the clerk's office has reviewed and filed the e-brief. For complete details, please see these rules at the link above.