When developing websites, it is useful to know which browsers your customers will be using. The best guide is your own usage stats, but if you don't have those, or want to see how your customers compare with a wider sample,
StatCounter publish figures based on "aggregate data collected by StatCounter on a sample exceeding 4 billion
pageviews per month collected from across the StatCounter network of
more than 3 million websites." They have a
nice graphing tool you can use to look at the browser war in different areas and over different time periods.
Worldwide, 19 May- 17 June Statcounter has IE7 still ahead (just under 32%) with Firefox 3 close behind.
Firefox is ahead of IE7 in Europe (36% to IE7's 27%):

IE7 has a bigger share in North America (38% to 28%)
IE8 has yet to get above 10% (has just reached thsi in North America, yet to get to 8% in Europe)
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