Online Bible Resources:
Bible Gateway – Provides a nice search feature with many translations and lots of additional information.
NET Bible – The New English Translation
Bible Crosswalk – Another nice search feature with many versions online, includes Strong's numbers!
Parallel Comparison – From the folks at Crosswalk – compare texts of two different translations!
Bible History.com – TONS of Bible information, history, maps, geography, timelines, etc etc etc
Public Domain Dictionaries:
Baker Evangelical Dictionary of Biblical Theology – From the folks at Crosswalk – one of the finest Dictionaries in use today!
Public Domain Commentaries:
Crosswalk Commentaries – Many public domain commentaries, including Scofield's notes and Wesley's notes!
Public Domain Concordances:
Crosswalk Concordances – Many public domain concordances, including Nave's and Strong's.
Bible Study Software:
E-Sword.net – A nice, basic system with many resources and a good search engine. FREE!
Gramcord.org – A nice tool to work with original languages, many versions and reference materials
Logos – The cream of the crop (high end)! $150 – $600.
Greek / Hebrew Information:
Lexicon– From UnboundBible.org, enter a word and determine the Greek or Hebrew meaning/equivalent
Foreign Language Versions:
Text available in MANY different languages, provided from the Bible Gateway folks