Paul, in Word 2007 the find dialog pops up, not the Word 2010 Navigation Pane.

AFAIK, the Find/Replace/GoTo dialog cannot be resized. You can make it larger by clicking on the "More" button. You can resize your Word window and drag the Find dialog outside that Window. So long as it isn't covering a found item, it seems to stay put. I suppose a macro could do this for you.

It will pop out of the way of any found text, if that helps. I know of no way to permanently position it. Using the browse object as Paul suggested, though, may meet your needs.