Several people on the Google-Mobile-Help group have noted that the Basic HTML link that used to be present at the bottom of each page has recently been removed. There is a workaround for this: go to http://mail.google.com/mail/h/ on your phone. You might want to bookmark this URL -- it's the only way to do some things, such as marking a message as spam, from your phone's browser. To return to Mobile view from Basic HTML view, click the Mobile link at the bottom of the page.
Another feature that seems to have gone away at the same time as the Basic HTML link is the number-key shortcuts for commonly-used commands. These shortcuts still work, but they are no longer displayed on the screen. They are:
1 - Reply *
2 - Reply to All *
3 - Forward *
4 - Archive **
5 - Mark Unread *
6 - Add/Remove Star **
7 - Trash Conversation **
8 - Compose Mail
(9 - nothing?)
0 - Go to inbox
* Only available when viewing a message
** Only available when viewing a message or conversation
Hope this information is useful to someone. And if anyone from Google is reading this, I would really like both those features back! You can make them a per-user configurable option.