Per Puppethead in the comments, Giffords’ 2010 Congressional opponent Jesse Kelly held a June 12 gun event that was billed as follows on the Pima County Republican website:
Get on Target for Victory in November Help remove Gabrielle Giffords from office Shot a fully automatic M15 with Jesse Kelly
Kelly’s website has apparently scrubbed the event , but here is the account from the Arizona Daily Star:
Jesse Kelly, meanwhile, doesn’t seem to be bothered in the least by the Sarah Palin controversy earlier this year, when she released a list of targeted races in crosshairs, urging followers to “reload” and “aim” for Democrats. Critics said she was inciting violence.
He seems to be embracing his fellow tea partier’s idea. Kelly’s campaign event website has a stern-looking photo of the former Marine in military garb holding his weapon. It includes the headline: “Get on Target for Victory in November. Help remove Gabrielle Giffords from office. Shoot a fully automatic M16 with Jesse Kelly.”
The event costs $50.
KVOA television in Arizona is also reporting that Rep. Giffords has died.
Update I: Gawker spoke to eyewitness Steven Rayle, who says one of the victims was “a kid no older than 10 years old”:
The event was very informal: Gifford had set up a table outside the  Safeway and about 20-30 people were gathered to talk to her. The gunman,  who may have come from inside the Safeway, walked up and shot Gifford  in the head first, “point blank”. According to Rayle, who is a former ER  doctor, Gifford was able to move her hands after being shot.
After shooting Gifford, the gunman opened fire indiscriminately for a  few seconds, firing 20-30 rounds and hitting a number of people,  including a kid no older than 10 years old. Rayle hid behind a concrete  pole and pretended to be dead. When the gunman apparently ran out of  ammunition he attempted to flee, but a member of Gifford’s staff tackled  him. Rayle helped hold the gunman down while waiting for the sheriff to  arrive, about 15-to-20 minutes later. The EMS came about 30 minutes  later. Rayle said he was “stunned” by how long it took medical help to  arrive.
Update II: Brendan sends this, which has apparently been scrubbed from Sarah Palin’s web page: