Preview 2011 Spa-Francorchamps, Belgium GP

Belgium F1 circuit its a mix of long straights and challenging fast corners, coupled with its picturesque setting and remains one of the most popular venues with drivers and fans alike, having hosted a Grand Prix as long ago as 1924. The weather is still notoriously changeable (it can often be simultaneously raining on one part of the track and dry on another) and Eau Rouge, with its high speed and sudden elevation change, maintains its reputation as one of Formula One racing's most technically demanding corners.
The old Spa circuit was essentially a speed course with drivers managing much higher average speeds than on other race tracks.
The Circuit de Spa-Francorchamps is the venue of the Formula One Belgian Grand Prix and the Spa 24 Hours endurance race. It is also home to the all Volkswagen club event, 25 Hours of Spa, run by the Uniroyal Fun Cup. It is considered to be one of the most challenging race tracks in the world, mainly due to its fast, hilly and twisty nature.

Technical detailes
The circuit probably demonstrates the importance of driver skill more than any other in the world. This is largely due to the Eau Rouge and Blanchimont corners, both which need to be taken flat out to achieve a fast run onto the straights after them, which aids a driver in both a fast lap and in overtaking.
The challenge for drivers has always been to take Eau Rouge-Raidillon flat out. Regular touring cars can take the corner at 160–180 km/h, Formula One at over 300 km/h -this is due to the huge amount of downforce on the cars.
Belgian Circuit has 7 km, 44 laps with a race distance of 308 km; 5 highspeed straches, 3 slow turns, 2 ideal spots for overtaking and a top speed around 315 km/h. Best Preview by Mark Webber:

Wikipedia History
Like the Nürburgring, Spa became notorious for fatal accidents, as there were many deaths each year at the ultra-fast track, especially at the 1960 Belgian Grand Prix where 2 drivers, Chris Bristow and Alan Stacey were both killed within 15 minutes (although Stacey's accident was caused by a bird hitting him in the face) and Stirling Moss had crashed at Burnenville during practice and was severely injured. The Ardennes Forest had very unpredictable weather and there were parts where it was raining and the track was wet, and other parts where the sun was shining and the track was completely dry.
In 1969, the Belgian Grand Prix was boycotted by F1 because of the extreme danger of Spa. The drivers demanded changes made to Spa which were not possible on short notice, so the Belgian Grand Prix was dropped that year. Armco was added to the track and sections of it were improved (especially the Stavelot and Holowell sections), just like Armco had been added for the 1969 Le Mans race. F1 would not return to Spa until 1983 on the modern track.
Eighteen Formula One World Championship Grands Prix were run on the Spa-Francorchamps circuit's original configuration, which was boycotted by F1 in 1969, before the revised circuit banished it to the history books in 1979. The lap record of the old triangle-shaped track is held by the French driver Henri Pescarolo, at an average speed of 262 kilometres per hour (163 mph).

Over the years, the Spa course has been modified several times. The track was originally 15 kilometres (9 mi) long, but after World War II, the track had some changes. The uphill U-turn right after the famous Eau Rouge corner called "Virage de Ancienne Douane" was eliminated and cut short, thus giving birth to the Radillon uphill sweeping corner. All changes made the final configuration of the old Spa circuit 14 km (9 mi) long. All these changes made Spa the fastest open road circuit in the world, and in the final years of the old circuit, drivers could average 150 mph (241 km/h) on the circuit. The biggest change, however, saw the circuit being shortened from 14 km (9 mi) to 7 km (4 mi) in 1979.
Spa was dropped from the Formula One calendar in 2006. The organiser of the event went bankrupt in late 2005, and therefore the planned improvements to the race track and paddock had not yet been made. The Wallonia government stepped in and provided the necessary funds, but too late for the 2006 race to take place.
Formula 1 returned to Spa for 2007, with a modified track layout. The Bus Stop chicane was moved back towards Blanchimont and the La Source hairpin moved forward. This allowed more space for the new pit lane. The modifications gave a longer start/finish straight
Modifications for 2010 season: New tarmac runoff was added to the inside and outside of Les Combes for the 2010 race, in line with the prevailing trends at other Formula One circuits.

Statistics
Fastest Laps
2001 1:16.723 Michael Schumacher
2004 1:45.108 Kimi Raikkonen (current lap record)
2002 1:47.176 Michael Schumacher
2009 1:47.263 Sebastian Vettel
2008 1:47.930 Kimi Raikkonen

Sebastian Vettel : races - 4, victories - 0, podiums - 1, poles - 0, fastest laps - 1, points - 10
Mark Webber : races - 7, victories - 0, podiums - 1, poles - 1, fastest laps - 0, points - 26
Lewis Hamilton : races - 4, victories - 1, podiums - 2, poles - 1, fastest laps - 1, points - 36
Jenson Button : races - 9, victories - 0, podiums - 1, poles - 0, fastest laps - 0, points - 8
Felipe Massa : races - 6, victories - 1, podiums - 2, poles - 0, fastest laps - 1, points - 35
Michael Schumacher : races - 14, victories - 6, podiums - 9, poles - 1, fastest laps - 4, points - 86
Nico Rosberg : races - 4, victories - 0, podiums - 0, poles - 0, fastest laps - 0, points - 12
Nick Heidfeld : races - 7, victories - 0, podiums - 1, poles - 0, fastest laps - 0, points - 16
Vitaly Petrov : races - 1, victories - 0, podiums - 0, poles - 0, fastest laps - 0, points - 2
Rubens Barrichello : races - 16, victories - 0, podiums - 2, poles - 1, fastest laps - 1, points - 21
Adrian Sutil : races - 4, victories - 0, podiums - 0, poles - 0, fastest laps - 0, points - 10

Now last year pole by Mark Webber:
1:45.778