An aide to Gov. David Paterson tells the Associated Press that Rep. Kirsten Gillibrand has been picked to fill Hillary Clinton's Senate seat.Paterson is expected to announce the appointment at noon in Albany. The aide spoke on condition of anonymity since an announcement wasn't made yet.The appointment will last until 2010, when a special election will be held to fill the remainder of the six-year-term.The 42-year-old Democratic congresswoman from eastern New York was first elected to Congress in 2006 and won re-election in 2008 by a sizable margin. Rep. Carolyn McCarthy is strongly criticizing the pick, saying Gillibrand's strong support of gun ownership rights put her at odds with most Democrats in the state. McCarthy says she will challenge Gillibrand in 2010 for the Democratic spot on the ballot if no one else does.Rep. Peter King is expected to seek the Republican nomination for the special election.