mail2twitter
This is a cool hack:
[from mail2twitter]What is mail2twitter?
mail2twitter is a free service that allows you to post tweets through e-mail, and the most important, from any email-enabled mobile device.
The only thing I don't like is that the subject line of the email is your twitter ID and your twitter password, so the password is being passed around as clear text. Would be better to have people actually set up accounts, and then match the 'sent from' address with stored twitter passwords.

Good idea although the "sent from address" doesn't mean you are the one sending the e-mail. A few clicks in your favorite e-mail application and you could be bill.gates@microsoft.com
Posted by: Jesper | March 29, 2007 at 06:21 AM
Hi, saw your post on Mail2Twitter, and your issues regarding putting login/password data in the 'Subject' line.
Here's a similar service that supports registration of "sent from" e-mail addresses, so you don't have to put login/password data in every e-mail: http://EmailTwitter.com/.
Posted by: Elliot | April 02, 2007 at 02:09 PM