iText is a Java library used as PDF engine in popular Frameworks such as Spring, jBoss SEAM, JasperReports, and many others. It's the de facto standard library if you are looking for PDF creation and manipulation.
The 2.1.3 release fixes most of the issues reported on the itext-questions@list.sourceforge.net mailing list in the past few months.
As far as new functionality is concerned, this release brings an HTML related code contribution by Lubos Strapko, plenty of new RTF stuff by Howard Shank, and some new features that were asked for on the mailing list and that were implemented by Bruno 'doctor iText' Lowagie ;-)