QTwitterClient is cross-platform and works on all platforms supported by Qt such as Windows, Linux, and Mac OS X, even mobile platforms like Symbian and Maemo.
Usage is very simple:
QTwitterClient *twitter = new QTwitterClient(this); twitter->setLogin(login); twitter->setPassword(password); twitter->tweet("I feel really good today!");QTwitterClient is free/open source software and licensed under LGPL 2.1 or later.
Check out QTwitterClient project page to get the source code. I will appreciate any feedback you have.
Update: Moved QTwitterClient project to Gitorious.