"In one of the most extraordinary days in Wall Street’s history, Merrill Lynch is near an 11th-hour deal with Bank of America to avert a deepening financial crisis while another storied securities firm, Lehman Brothers, hurtled toward liquidation, according to people briefed on the deal."
This is a summary lead because it contains most of the five W's/H. It also is written to grab the reader's attention without really telling the entire story - though it tells most of it - Lynch is closing in on a deal with Bank of America while other companies are nearing the end of their line. It makes for a good story, and a good lead.
"MOSCOW – An Aeroflot flight crashed in a central Russian city on Sunday shortly before landing, killing all 88 passengers and crew on board, officials said."
This is a short report because it's essentially something you'd see on a crawler on CNN or MSNBC. It gives you the time, the date, what happened and where it happened in one concise sentance, which is characteristic of short reports. It also works well as a short newspaper brief, which is really what it's being used for.