The 3 part qualification format is well explained here. I like the format actually hope it is more interesting than last year. The qualification format:
Part one: All 20 cars may run laps at any time during the first 15 minutes of the hour. At the end of the first 15 minutes, the five slowest cars drop out and fill the final five grid places.
Part two: After a five-minute break, the times will be reset and the 15 remaining cars then will then run in a second 15-minute session – again they may complete as many laps as they want at any time during that period. At the end of the 15 minutes, the five slowest cars drop out and fill places 11 to 15 on the grid.
Part three: After another five-minute break, the times are reset and the final 20-minute session will feature a dramatic shootout between the remaining 10 cars to decide pole position and the starting order for the top 10 grid places. Again, these cars may run as many laps as they wish.
As an added twist, an element of suspense and pit strategy remains entwined in the new format. In the first two 15-minute sessions, cars may run any fuel load and drivers knocked out after those sessions may refuel ahead of the race.
However, the top-ten drivers must begin the final 20-minute session with the fuel load on which they plan to start the race. They will be weighed before they leave the pits, and whatever fuel they use in the 20 minutes may be replaced at the end of the session.
In other changes approved by the Council for 2006, the rule limiting a driver to a single set of tyres for qualifying and the race will be dropped. Tyre changes will be allowed during the race, though drivers will be limited to seven sets of dry-weather tyres during the weekend. Tyres used in qualifying and the race must be of the same specification.