The following is a small sample of the growing set of tools, projects and applications utilizing OWL.
Commercial Ontology Support Tools
Altova's SemanticWorks
Altova SemanticWorks 2006 is the ground-breaking visual RDF/OWL editor from the creators of XMLSpy. Visually design Semantic Web instance documents, vocabularies, and ontologies then output them in either RDF/XML or N-triples formats. SemanticWorks 2006 makes the job easy with tabs for instances, properties, classes, etc., context-sensitive entry helpers, and automatic format checking. It is the sensible way to put the Semantic Web to work for you.
SNOBASE is an ontology management environment developed by IBM Alphaworks. It provides a mechanism for querying ontologies and a programming interface for interacting with ontologies written in RDF Schema and OWL.
Network Inference has developed a set of tools around their Cerebra Inference engine that allow for the development and use of OWL ontologies.
Tucana Technologies Inc. has developed a scaleable RDF triple store which includes some OWL inferencing and is adding more.
Demos / Portals
AIFB SEmantic PortAL - The Institute AIFB web site of the University of Karlsruhe provides annotated pages which contain dynamically generated machine processable content in form of OWL annotations.
The AKT Portal at the University of Southampton is largely based on ontologies, and is now using OWL.
The University of Maryland Baltimore County (Finin) has developed two demos using OWL ( Finin 7May)
BioPax - A Data Exchange Format for Biological Pathways has been using OWL
The W3C tech reports - related to the "multimedia collections" use case
( The MINDSWAP project web site) uses OWL to generate all the web pages and "custom home pages" for members of the research group, as well as for doing photo markup. ( Hendler 6May)
The OWL-generated Comment Status List submitted for the CR request for OWL was generated by a combination of OWL tools.
Reasoners
KAON2 is a reasoner for OWL extended with the DL-safe subset of SWRL; it also provides an OWL API.
FaCT -- a DL reasoner. see WonderWeb project, Bechhofer 15 Sep.
Racer -- a DL reasoner. see Horrocks 12Sep
Cerebra from Network Inference - owl syntax checker, nearly complete OWL DL Horrocks 12Sep
cwm -- useful but incomplete OWL Full
Euler -- useful but incomplete OWL Full,see De Roo 11 Jul: 51 / 234 tests
surnia -- OWL full reasoner based on otter. Hawke 26Aug
Jena/HP ( Reynolds/HP 7 May)will support OWL reasoning.
Vampire Horrocks 17 Jul - uses a first-order theorem prover to do OWL DL
Pellet is a reasoner built in Java that was designed specifically for OWL reasoning. Hendler/Sirin/Parsia 15Sep).
SWI-Prolog Semantic Web Library contains owl.pl - an OWL reasoning package.
F-OWL is an f-logic based Owl tool from UMBC.
E-wallet is an e-commerce and mobile computing tool based on a rule-based OWL reasoner.
Parsers / Validators
dlpconvert is a tool for the conversion of the Horn fragment of OWL (called DLP) from XML or RDF syntax to Prolog syntax.
owl species validator/parser. seems to be a conforming owl syntax checker per Bechhofer 10Sep
OWLP seems to be a conforming owl syntax checker, per Patel-Schneider 16Sep
Jena: almost conforming ( Carroll/HP 6 May )
BBN OWL Validator
IC Instance Creator, ConvertToRDF, and SMORE use an OWL parser developed at the University of Maryland MIND Laboratory.
Editors
Altova's SemanticWorks
Altova SemanticWorks 2006 is the ground-breaking visual RDF/OWL editor from the creators of XMLSpy. Visually design Semantic Web instance documents, vocabularies, and ontologies then output them in either RDF/XML or N-triples formats. SemanticWorks 2006 makes the job easy with tabs for instances, properties, classes, etc., context-sensitive entry helpers, and automatic format checking. It is the sensible way to put the Semantic Web to work for you.
The Protege has developed an OWL plugin.
Construct from Network Inference Complete OWL-DL (White 15Jul)
SMORE is a markup tool that produces OWL documents
cwm .n3 -> .rdf produces conforming OWL Full documents
API
OWL API ( bechover/volz 7 May)
Jena ( Reynolds/HP 7 May)
Cerebra from network inference
Ontologies
SchemaWeb provides a comprehensive directory of RDF schemas and OWL ontologies to be browsed and searched by human agents and also an extensive set of web services to be used by agents and reasoning software applications that wish to obtain real-time schema information.
DAML Ontology Library which organizes hundreds of ontologies in a variety of different ways (keyword, organization, submission date, etc.)
Swoogle is a search engine for Semantic Web documents, including OWL ontologies, built by the University of Maryland Baltimore County under funding from the National Science Foundation.