There are a couple things I know are issues that I want people to keep in mind.
1) Changing phone numbers and passwords. If you try to change your number in the extensions preferences and it doesn't seem to work, go into the firefox preferences and remove the saved entry for "http://minuteminder.cingular.com." For a little bit of help with this check out this site. Note, you don't need to clear all your passwords, just the one.
2) This is similar to the first point. If you're using an additional passcode and you mistype it, the extension doesn't prompt you for it again, at least not necessarily. Your best bet is to go into Firefox's preferences and delete that entry.
3) Right now, the extension only really applies to each window separately. So, when you refresh it on one window, it is not refreshed on all the windows. This has always been the case, but I thought I'd make sure everyone knows about it to hopefully save any confusion.
Let me know if there is anything else: cingularminutes AT gmail