Im running Solr 1.4 on Ubuntu 10.04 (installed via apt-get solr-tomcat) and it seems to be working fine. Im having some difficulty finding any coherent info on how to index
Take a look at the Solr wiki, it's a pretty thorough documentation.
In particular see the ExtractingRequestHandler, which allows you to index binary files like Word and PDF documents. Here's an introduction to the topic.
If the wiki isn't enough for you, there's also a great book about Solr.
I have found the same challenges with the core documentation, but I came across this very useful reference guide from LucidImagination, which helped to clarify a lot of thing about SOLR:
http://docs.lucidworks.com/display/solr/Apache+Solr+Reference+Guide
Processing rich documents with Solr: http://wiki.apache.org/solr/UpdateRichDocuments