The AP is reporting:

Lieberman will deliver a speech when Republicans gather in St. Paul, Minn., to nominate McCain for president, a party official told The Associated Press on Wednesday. The official requested anonymity because a formal announcement had yet to be made.

Asked during a visit to Georgia whether he would be speaking at the convention, Lieberman smiled and said: "it's quite possible, but I'll let them announce it."

Not really a surprise and it's probably silly to try to read any VP news in this. In other Lieberman news, the senator left today for a tour of Georgia, Poland and Ukraine, which have been in the headlines of late.