There are many evangelical Bible commentaries available online, including the Asbury Bible Commentary and the IVP New Testament Commentary Series. Matthew Henry's Commentary on the Whole Bible is also available online.
The Asbury Bible Commentary is an evangelical commentary in the Wesleyan tradition. It covers the Old and New Testaments, and contains contributions from over 50 authors. The IVP New Testament Commentary Series is an extensive evangelical Bible commentary that contains historical information and suggestions on the application of a given passage to the reader's life. This commentary also addresses interpretive controversies.
First released in 1706, Matthew Henry's Commentary on the Whole Bible contains verse-by-verse analysis and reference information. Complete and abridged editions are available online.