The Amoeba Project

An attempt to create semantic data.

Some resources about RDF

http://www.xml.com/pub/a/2001/01/24/rdf.html
For more on the Semantic Web, see other SemWeb articles on xml.com, the W3C, and their Semantic Web mail list.
The W3C specifications for RDF form the definitive guide, but other sources are a better bet for learning RDF: this tutorial, the site rdf:about, and the book Practical RDF.
There are many toolkits available in a variety of programming languages for working with RDF. This page lists most of the toolkits.
RDFS and OWL are W3C vocabularies used to create schemas or ontologies. SchemaWeb maintains a list of other vocabularies.
SPARQL is the new query language for RDF. There is an article on SPARQL right here on xml.com.
Automated inferencing is one main line of interest for RDF. Cwm and Euler are two tools for inferencing over RDF, using the RDFS and OWL schemas and other general rules. Pellet is an OWL-DL reasoning engine.
Some existing RDF datasets are listed here and on rdfdata.org.