Pushit is a free plugin for WordPress capable of sending a blog post to a friend via SMS or e-mail.
Pushit adds support for registration with cell phones. This means that you can verify your blog visitors and send them their password in a text message (SMS).
Pushit adds post recommendations via SMS, e-mail and social bookmarks like Facebook, Twitter and Bloggy. As a bonus, Pushit also gives you a print function and a set of related RSS links for a particular post.
The third major feature is the compact mobile viewport for your web site. The mobile version is a small publishing system within Wordpress. The site administrator can adjust custom field support, user login, comments, search and other features.
The software works with almost all operators worldwide, but requires registration at Multimobil
Pushit is currently in closed beta period. You can try Pushit as an end user, or apply to the beta program as a content provider.
The first public beta is scheduled for 30th of April 2009. After this date, Pushit will be available under the GPL v3 licence from wordpress.org, where you also can find the official FAQ.