Bible History Online - includes book studies and commentary on OT Canon and NT Canon, as well as many essays on "the stuff between the lines".
Prof. Ralf Klein's Links - includes links to important sites, exercises, and more.
World Wide Search of the Bible - provides many downloadable essays and commentaries on the Bible - excellent for research.
Encylopedia of the Orient - exactly what the name says, including a helpful link to maps of the orient.
Washington State University - ancient World Culture Site. Click the "references" section.
Internet Ancient History Sourcebook - not all the links work, but the ones that do have good information!
Biblical Heritage.org - Similar to "Bible History Online" except a bit more comprehensive and a bit more scholarly.
Jewish Encylopedia - A searchable on-line Jewish encyclopedia. Older, but still quite useful.
Johannine Letters - Commentary, essays, and indepth research of Johannine letters as well as the Gospel of John.
Greek New Testament with Search Engine. Several sights are linked to this helpful page from the University of Birmingham.
The link within the above link that leads to research links for Biblical Essays
Jesus Links
The Jesus Project. Research on the historical Jesus from a sociological perspective.
Jesus in Early Christian Gospels
Historical Jesus: A Reconstruction
Frontline: From Jesus to Christ
Apocalypticism in the Bible. An excellent resource on from Frontline (PBS).
Did Jesus Exist? - a one-sided but intriguing investigation into the proof of Jesus' existance.
Parallels of Thomas and other Gospels
Frequently asked questions about the Gospel of Thomas
Concordances
Search several differnt translations/versions of the Bible
Ancient Maps sites