For current, annotated federal and state statutory codes, use Westlaw and Lexis. Recall that annotated codes include not only the statutory text, but also citing references and Notes of Decisions. Citing references include every case and secondary source that has cited the section, whereas Notes of Decisions consist of select case summaries drafted by the Westlaw or Lexis editors.
The full-text of the U.S. Code (unannotated) is also available on:
State statutory codes (unannotated) are also available on state legislature websites.
No matter what strategy you use to find a section, use the table of contents to browse nearby sections!
Start with resources selected by editors of the annotated codes.
Historical versions of state statutes are also available on Westlaw & Lexis. Coverage varies by state, but generally begins in the mid-1980s. Meanwhile, for early, historical state codes, try HeinOnline's State Statutes: A Historical Archive library.
Finally, the PLRC has historical state statutes in print and on microform. Ask a reference librarian for assistance.
If you need to research uniform laws, visit the Uniform Law Commission website. Here, you will find both the text of uniform laws and enactment status in specific jurisdictions.
Uniform Laws Annotated is available on Westlaw. It contains the text of uniform laws, annotations, and information about adoption by states, including citations to state codes.