The Cleveland-Marshall College of Law offers a European Union Law Resource Guide (latest update June 2009).
Here are my impressions:
The Guide is clear and simple enough not to intimidate the budding writer. The reader sees the central role of the general Europa portal and the legal portal Eur-Lex.
I wondered at the order of presentation of the various EU Treaties.
The Constitutional Treaty (2004) could have been mentioned in the past tense.
The Treaty of Lisbon: It would be natural to link to the consolidated version published in the Official Journal of the European Union 9.5.2008 C 115.
The EU Charter of Fundamental Rights becomes legally binding only if the Lisbon Treaty enters into force, but I would link to the latest version and the explanations, published OJEU 14.12.2007 C 303.
There are useful links to other research guides.