I just spent a few minutes looking for these fonts and found them. Found the Catull to be correct (for "Google" and the "G" in Gmail). As far as the Myraid Pro (for the "mail" in "Gmail"), it looks like it was used for the "ail" in "Gmail", and to an extent, the "m" as well, but more or less "Photoshopped" to match the envelope. The letters after it ("ail"), look as if they've been slightly "squished", so-to-speak. I don't know the term for that. I'm not a graphic designer. Otherwise, the font looks correct.
At first, I absolutely despised Google. I thought it was just too plain looking and unattractive. It took me a while to get off of Yahoo's search engine and take advantage of Google. I still find myself hitting Yahoo for everything else because everything I "need" is right there.