Some exciting news about Patent Lens, one of my favourite patent databases...
Patent Lens now includes bibliographic data and full-text images for Australian A and B docs from 1998 to the present. As far as I can tell, this is about the same coverage as esp@cenet (although country code plus year searches are giving me some very odd results for pre-2002). Patent Lens now covers some 7 million patent documents, including US, European and WIPO.
In another very exciting development, it is now possible to search gene sequences using NCBI's BLAST search software. This very cool and powerful tool allows users to search DNA and amino acid sequences in US patent documents. Definitely check it out. Biochemists and biotechnology researchers will love it.
Unfortunately, Patent Lens still doesn't include IPC classifications, making it virtually impossible to do a focused search by subject matter. You can search IPC codes (and national classifications) against the front page text, but this approach is inaccurate and unreliable. Despite this shortcoming, Patent Lens is still one of the most useful and innovative open-source patent search tools on the web.