ebsites of interest

Patents:

Espacenet
Espacenet is the EPO's free website of published patents and patent applications. It is searchable by key word and by patent number. It also offers equivalents, some legal status information and, for European applications, links to EPOLINE.
US Patent and Trademark Office
This is the main website of the US Patent and Trademark Office. Here you can also search granted patents and pending published applications by searching here:
USPTO Search
To get the images, you need to download a viewer for the TIFF flies the USPTO uses. However, full texts are searchable (which can be a blessing or a curse, depending on the circumstances).

EPOLINE
The EPOLINE Register of the EPO can be searched for details of European patent applications. All details and documents are downloadable (communications between the EPO and the applicant, oppositions, appeals).

PAIR
PAIR (Patent Application Information Retrieval) is the US Patent Office's equivalent of EPOLINE. Again, all details are downloadable.

WIPO PATENTSCOPE
WIPO's PATENTSCOPE provides a way of searching applications filed under the Patents Cooperation Treaty. PCT information appears here before it appears anywhere else.

J-Plat Pat
The Japan Platform for Patent Information replaces the JPO's old IDPL and offers more searching possibilities. One improvement is that it is possible to use the Gregorian calendar year as well as the Imperial Reign year for older applications (publication no. 1983-123456 works as well as the original S58-123456). You can get an English language abstract and bibliographic details, and for newer applications a machine translation, which may (or may not) be helpful, but which is often amusing.

DPMA
The German Patent Office (DPMA) register is searchable for German patents, trade marks and designs.

INPI
INPI, the French Patent and Trade Mark Office, has limited searching capabilities.

IPO
The UK Intellectual Property Office has searchable databases for UK patents, trade marks and designs.

SIPO
SIPO, the China Patent and Trade Mark Office, now offers searching services.

Free Patents
Free Patents Online offers, er, free patents online.

Korean Patent Office
The Korean Patent Office (don't laugh, along with the EPO, the USPTO, SIPO and the JPO, the Korean Office is one of the "big five") offers searching services, plus machine translations of Korean patents/applications (but you have to pay for those).

EPO
The European Patent Office's site has lots of information, including a database of EPO case law from the various Boards of Appeal.

Research Disclosure
If you only want to publish, and as quickly as possible, Research Disclosure is the place to do it.

Spanish Patent Office
The Spanish Patent Office offers searching not only of Spanish patents, but also many of the Spanish-speaking countries of Latin America. Unfortunately only en Espagñol.

International Patent Classification
The International Patent Classification is a way of searching patents without resorting to keywords. It is unwise immediately to be too specific as to sub-sub-sub-class, as classifiers can make mistakes just as much as everyone else, but the broader classifications work well.

US Classification
The US patent classification is different from the IPC, but it will shortly be superseded by the

Cooperative Patent Classification
A joint USPTO-EPO effort to produce a common classification.

Intellogist
A site produced by specialist patent services firm Landon IP. It includes FreshPatents, http://www.freshpatents.com/ a free alert service.

Trade Marks:

OHIM
OHIM (Office for Harmonization in the Internal Market), otherwise known as the Community Trade Mark Office, has a searchable site.

TESS
TESS (Trademarks Electonic Search System) is the US Patent Office's trade mark search system.

ROMARIN
ROMARIN is WIPO's way into International (Madrid) trade mark applications.

WIPO NICE Classification
Correctly classifying trade mark goods and services is a must, and the Nice Classification (the French town, not its attractiveness) is an essential tool for getting it right. It is available in a whole battery of language and with numerous guides.

Markify
A very useful search service that gives a world-wide search, and even will search for near-phonetic equivalents, so PONGO will also find PAWNGO and POMGO and BONGO. Alas, no longer free.

Trademarkia
A US service that is useful, but really no more useful than the USPTO's own TESS.

TMView
A free service covering European national, US and International marks, and a few others. Free!

Serion
A Thomson Reuters continuation of the old (and very useful) Saegis system. It will let you search for free, but you have to pay to see the results.

Others:

Pipers
The New Zealand patent attorney firm of Pipers has kept a well-regarded list of patent attorneys and IP offices for a very long time. Want to file in a country where you have never filed before? Pipers will have a selection of attorneys for you.

Logo Expert
Need a logo drawn or designed? These folk took my design for the Teemacs logo and made it presentable. Extremely helpful - I cannot recommend them sufficiently highly. They were also much too polite to tell me what they thought of it� and they speak excellent English.

DIALOG
DIALOG is the world's premier commercial database system. It costs money and you have to join it. Even then, some of the patent databases are wickedly expensive (Derwent). Relatively cheap are the excellent TRADEMARKSCAN databases, covering both US, International and national European trade marks. Also included are JAPIO (English language Japanese patent abstracts) and Chinese Patent Office abstracts.

STN
What the Karlsruhe-based STN loses to DIALOG in general coverage, it makes up in scientific and patent coverage. To the best of my knowledge, it is the only database network to offer the actual abstracts of Chemical Abstracts online (DIALOG offers only bibliographic information). It also offers Derwent, as indeed anyone who seriously covers the patent literature must do.

Questel
ORBIT, a challenger for DIALOG's crown in the 1980s when database networks got going, has receded into the distance and was acquired by Questel, itself an offshoot of France Telecom. It has Derwent and a variety of other patent databases.

SecureyourTrademark
A useful general US site provided by a US attorneys office in LA, giving general guidance on all matters of (US) intellectual property. (Grateful thanks to Sarah Lannister of Arizona for bringing this to my attention).