What font does WordPress use? The closest font you can get for the WordPress logo is Mrs Eaves XL Serif Bold font.
Originally designed in 1996, Mrs Eaves was Zuzana Licko’s first attempt at the design of a traditional typeface
Free alternative fonts for WordPress logo:
The closest free font you can get is Scheherazade Font.
About free fonts:
Copyright (c) 2004-2011, SIL International (http://www.sil.org/)