There are several reports at Google Custom Search Help and Google Web Search Help with searchers who use Internet Explorer version 6 on their PC and are claiming that Bing has hijacked the search feature in the toolbar.
Several users are claiming that since Bing was launched, even though Google was their default search provider in IE, Bing has taken control. Even worse, when they try to change it back from Bing to Google, it does not work.
Here is one post:
Had Google set as my default browser. woke up this morning to discover that BING had hijacked this feature. cant change it via: search/customize on the IE tool bar. all I get is a windows live page saying Ooops.
There is no official explanation from either Microsoft or Google, as of yet. Matt Cutts of Google did tweet about the issue. A Microsoft individual did tweet back saying the "folks have escalated your concerns."
Update: We have a statement from Microsoft on this issue:
We're aware of the issue with IE6 and Bing and are investigating a solution. This issue is not impacting IE7 or IE8 users. We respect user choice on search providers in IE and all browsers, and designed IE to enable that choice. We will provide an update soon on this issue, and we apologize for any inconvenience it has caused. In the meantime, we encourage customers to upgrade to IE8 here. Alternatively, Firefox users can install the add-in for Bing here.
Update: Microsoft emailed me again at 2:45am on June 3, 2009 to inform me the issue is now resolved with IE6. The issue was server side, so the fix was able to be pushed out remotely to all infected browsers.