It would be nice to share some naming conventions for direct messages with Twitter. For example, people are really used to starting an SMS with "d" for a direct message to someone. You guys use "m". Maybe that's a standard somewhere else. Anyway, just a suggestion.
How about IM update from GTalk in the same mode as the email updates. For those of us on the move who can't use SMS yet, but can access GTalk (e.g. from Blackberry 8000 series etc.), it would seem like a reasonable halfway house. Email is OK, but I don't fancy having a load of sent messages in my work mail account when I could just be banging an XMMP message Brightkite's way :)
When I send the SMS command ? Starbucks or ?Starbucks from my confirmed mobile number, I get no response. I haven't tried other commands, but it seems like many people are having trouble with using commands from SMS. I'm on T-Mobile, if it matters.