The most used Apple software I use is Apple's browser named Safari. Safari, is currently not supported by Google's email, GMail. A thread over at WebmasterWorld discusses a rumor at MacWorld's MacCentral that says:
Brin noted that he was "embarrassed" that Gmail's beta doesn't support Safari, but said that they will add Safari support before its public release. "We're going to make it work with Safari and that's one of the high priority things," Brin told MacCentral. "Iíve heard that you can sort of get it to work if you're desperate. I want to fix that, and I want to make it work really well."