I find another way of updating your twitter from your mobile phone, but this is only applicable for Globe users here in Philippines. I see that they started to offer this service way back August 26, 2008. But I have not seen Globe promoted this service. I guess they thought twitter is not really that big here in the Philippines.
If you want to try this service, you need to register first by sending TWITREG <USERNAME> <PASSWORD> to 2370 which will cost you P2.50. To send your tweets, text TWIT <MESSAGE> to 2370. It’s still P2.50/twit. You can see more details here.
Owkei, I registered and tried sending a twit. It gave back a message saying, ‘Sorry this service is temporarily unavailable. Please try again later.(2)’
It looks like it’s not reliable. Probably, the reason why they have not widely promoted it. It might still be under construction. But it’s almost a year since they started offering this service, it should be something more working right now I guess. At least, Globe knows about Twitter unlike Smart who looks like they have not heard about Twitter. I have not found anything about twitter in the Smart website.