Oh man, that's really bad. I rarely use the GMail app, so I hadn't run across this particular limitation yet.
I found a forum thread where someone found a sequence of interactions that work around the problem, but select/copy/paste really should be in the app's menu, like they are for the browser:
Summary: You can use Shift-S to activate select mode, then use the scroll ball to select. (On a keyboardless phone, hold "menu" until the soft keyboard comes up, then press Shift-S to activate select mode.)
I found a forum thread where someone found a sequence of interactions that work around the problem, but select/copy/paste really should be in the app's menu, like they are for the browser:
http://www.google.com/support/forum/p/Google%20Mobile/thread...
Summary: You can use Shift-S to activate select mode, then use the scroll ball to select. (On a keyboardless phone, hold "menu" until the soft keyboard comes up, then press Shift-S to activate select mode.)