This belongs in a different section. This is the themes section, but you are new, so I won't "pounce" on you haha.
Btw... this is a big discussion going on right now! so, here is the link to the thread in which this "issue" is being discussed. Though to answer your question, Verizon and Microsoft PUSHED bing to our phones and made it the only search provider... quite a gutsy move if you ask me....
Okay I need to add my $.02 to the above post. First, the icon push and search engine prioritization happened at separate times. The Bing icon does *nothing* unless you install it. Don't like Bing, hide the icon.
As far as the search engine yes, RIM and MSFT have an agreement by which RIM will offer Bing as the native browser search engine. If you don't wish to use Bing you can: 1) set google.com as your home page for the native browser; or 2) browse to google.com on the native browser->BB Button-> Add Bookmark. That gives you two options - either load google.com directly when you launch the browser (so you never encounter Bing), or launch the browser and go to your Google bookmark (so you never encounter Bing.) Just throwing some options out there up front, yet again, before another waste of a thread is created. Good luck.