Duncan Riley's recent stats snapshot of blogging world-wide reports as of Oct 05 says that there are 100 million blogs around the world.
Some locations and blog counts:

• Australia: approx 450,000
• Austria: approx 20,000
• Belgium: approx 100,000
• Brunei: less than 3,000
• Canada: approx 700,000
• China: 6 million and growing
• Croatia: approx 50,000
• Czech Republic: approx 10,000
• Denmark: approx 15,000
• Finland: approx 100,000
• France: approx 3.5 million
• Germany: 300,000
• Greece: less than 5,000
• India: approx 100,000
• Iran: 700,000
• Ireland: approx 75,000
• Italy: approx 250,000
• Japan: at least 5.5 million
• Malaysia: approx 20,000
• Philippines: approx 75,000
• Poland: approx 1.5 million
• Russia: approx 400,000
• South Korea: approx 20 million
• Spain: approx 1.5 million
• Ukraine: 50,000
• United Kingdom: 2.5 million
• United States: approx 30-50 million

For more info, check out the detailed view, which includes data sources.