Keyboard shortcut to search for text in MS Outlook 2007

You can do this by pressing F4.

Under this Link you can see every Shortcut, Outlook has.

As mentioned already, F4 produces the Find window when in a message viewing window (not the main one). In fact, that key works in Outlook 2016 as well.

If you're wondering why Outlook doesn't use Ctrl+F, see Raymond Chen's blog post Why does Outlook map Ctrl+F to Forward instead of Find, like all right-thinking programs?, which discusses this part of the early history of Outlook.

Back in those days, the Ctrl+F keyboard shortcut did indeed call up the Find dialog, in accordance with convention.

And then a bug report came in from a beta tester who wanted Ctrl+F to forward rather than find, because he had become accustomed to that keyboard shortcut from the email program he used before Exchange.

That beta tester was Bill Gates.

And so it was changed.