This LibGuide provides a brief overview of the UCC's history and its application by the states. This guide also lists a variety of sources for information concerning the UCC ranging from websites to printed materials.
This link will direct you to a free to access copy of the UCC provided by the Cornell Legal Institute. While the code does not have comments or annotations with it, the whole of the UCC is available as well older versions of the code.
Westlaw and Lexis
WestLaw and WestLaw Next allows access to the official UCC text throught their databases.
LexisNexis has the official text available in its databases as well as other resources covering the UCC.