You can increase or decrease the text size in Outlook on the fly using the same technique that works in your browser. Since everybody else seemed interested, I figured this qualifies as a stupid geek trick that I'll share with you today.
If you are unfamiliar with how the browser trick works: you can use Ctrl and the mouse wheel in your browser to quickly zoom in, which increases the size of the text and images on the screen. This same technique works in the Outlook email view.
Using the Quick Zoom
Just hold down the Ctrl key while scrolling your mouse wheel over top of the preview pane… and the text will magically increase in size!
This also works for messages in a new message window, although you might note that HTML emails don't scale quite as nicely.
I find that this technique works out well for reading the tiny fonts in some emails, but it's mostly just a fun trick to show off to your friends or co-workers.
Note: Using the Ctrl and + or - keys works in the browser, but doesn't work in Outlook
