National Journal has the details, such that they are:
President Barack Obama will travel to Tucson, Ariz., on Wednesday to commemorate the victims of the shooting that led to the deaths of six people and many injuries, a senior administration official said. The official spoke on condition of anonymity because the White House had not authorized anybody to announce the trip.
The official could not provide details of what the president would do. Earlier in the day, White House officials said they expected the president would find ways throughout the week to commemorate victims, including Rep. Gabrielle Giffords, and to speak to the circumstances surrounding the shooting.
Since news of the incident first broke Saturday, the White House canceled several scheduled presidential events, including an economic policy discussion in upstate New York tomorrow.
Hardly a shock, and glad to see he will be going down to presumably meet with the families of the slain and injured. Rep. Giffords appears to be the remaining injured person who is still fighting for her life. Keep her in your thoughts. I've been a fan of hers since she came on the scene in 2006; a very impressive person who I thought back then had a bright future ahead of her in politics. Though that is on the back burner for now, I have no doubt she'll make a strong recovery.
Edit: NBC and CNN, among others has confirmed.