I had to do it once and now the time came. Floating around hundredths of unread mails for Gammu is not a way to go. I'm just middle of processing it, but most of you will get just generic reply, asking you to either file bug report to bug tracker or to write to mailing list. There is simply no reason why so much communication should be private between me and you. I think this is generally valid for any open source project, it usually does not make sense contact main developer directly when there are more appropriate ways to communicate.
If you find a bug or something does not work, simply report it! If you can search for duplicates before it is even better and you might be able to include some additional information, but even if you skip this step, it is much easier to track problems in bug tracker than in mailbox. Also in bug tracker the issue will not disappear until it is not fixed, in mailbox, it gets quickly out of focus and I will forget it.
Once more: If you've found a bug, report it!
If you have some question, you have much better chance to receive answer on mailing list. Simply there are more people hanging around and somebody might have already seen the problem. What is another good thing on mailing list is that they have archives, so that you can look whether somebody did not solve similar problem before. Also others will be then able to find your solution.
Summary again: If you have a question, ask on mailing list!