Bradley Manning is currently being held at a military jail in Quantico, Virginia, outside of Washington, DC.
Perhaps the most serious of the additional charges is an allegation of aiding the enemy. The army benchbook (PDF) for military judges says that the crime is punishable by death. The charge requires that any "intelligence" given to the enemy is, at least in part, true.
"Enemy" is defined as not only opposing forces in time of war, but also a "hostile body" and "civilians as well as members of military organizations.