Lucene 2 is mostly a bugfix release from v1.9.1 which came out March 3rd. The Lucene project follows a more conservative release cycle than some other projects. A large number of major enhancements and optimizations over the previous 1.4.3 release were introduced in version 1.9 (released Feb 26), allowing a few months for adoption and bug fixing for a very stable version 2 to carry the project on for some time. Lucene 1.9 also deprecated some features from previous versions which are now completely removed in version 2.
Lucene was started and is currently led by Doug Cutting, who has been working in the search field for over 16 years, having done similar work at Xerox PARC, Apple, and Excite. Lucene began in 1998 when Doug took some time off from Excite to write Lucene as a way to learn Java. Lucene became an open source project on source forge in 2000 and joined Apache in 2001. The Java community is lucky to have someone like Doug who is passionate enough about search technology to write and release such quality software to the open source world for free.