According to the 7/30/12 NASA article NASA Television to Air Upcoming Cargo Ship Launch to Space Station "ISS Progress 48 is scheduled to launch at 3:35 p.m. from the Baikonur Cosmodrome in Kazakhstan. It will dock later that day at 9:24 p.m. in a test of an abbreviated launch-to-rendezvous schedule designed to reduce the typical two-day flight between a launch and docking."
What is important in this test is that if successful it would be used for future Soyuz crew member flights to the International Space Station.
NASA will be covering the launch on NASA TV for this Progress cargo ship, via a Soyuz U rocket, beginning at 3:15 p.m. Eastern Daylight Time (EDT) on Wednesday, August 1, 2012.
And, the docking and rendezvous of the ship to the ISS will begin at 8:45 p.m. later that same day.
NASA states, "Expedition 32 Commander Gennady Padalka of the Russian Federal Space Agency and his five crewmates, including NASA astronauts Joe Acaba and Sunita Williams, will monitor key events during Progress 48's rendezvous and docking."
Since this is a test of the new system, Russian flight controllers monitoring the launch and flight of the Progress 48 spacecraft will decide during the flight whether or not to revert to the traditional two-day launch-to-rendezous plan.
If the old plan is used, then the spacecraft will dock to the ISS on Friday, August 3, 2012. NASA will provide coverage either way on NASA TV.