I was using a Verizon demo Motorola Droid today and ran into the following issue. I used the Browser to access www.gmail.com and was unable to zoom in on this page. As soon as I went to any other webpage, I was able to double tap to zoom (or use the zoom controls). I went back to gmail.com and still no ability to zoom.
I have seen other complaints about the native gmail application not having adjustable font size, but didn't expect issues with the web based access.
Is there a setting or trick to bringing up the zoom controls?