In Europe, MSIE7 and Firefox 3 are effectively tied for the lead as the most dominant browser, followed distantly by MSIE6. As in North America, MSIE8 has substantially increased it's market share since its March 19 2009 release, but it has not caught up to Europe's favorite son, Opera 9.6.
What is clear is that MSIE8's gain is MSIE7's loss. Comparing March 1-19 with April 1-19, the shift away from MSIE7 is almost equal to the shift to MSIE8, meaning that people that are upgrading to MSIE8 in Europe are doing so, in the most part, directly from MSIE7.
There is little or no change to the MSIE6 install base, indicating that this is an entrenched population, likely in large corporations or government agencies.
Like in North America, the big factor to watch is how quickly the MSIE6 population decreases. Europe already has an entrenched population of alternative browser users, mostly with Firefox 3. When Opera 10 and Firefox 3.1 are released, it is likely that these people will move directly to these browsers.
What remains to be seen is how the strong anti-Microsoft sentiment in Europe affects the adoption of MSIE8.