the speaker, Pelosi, signed a notarizes Certificate of Nomination. Apparently two different versions.
Pelosi signed the documents as President of the Democrat National Convention, not as Speaker of the House. It is tradition that the President of each party's convention sign the documents sent to each State which notify that state the name of the nominee. There were actually several different versions sent to different states since different states have different language called for in their various statutes.
Some posters have said that Pelosi signed the documents as Speaker of the House, and Boehner can just not sign the documents to keep Obama off the ballot 2012 if he is not satisfied Obama is eligible. That is another birther myth.