Grollier's site The American Presidency presents four high-quality biographies of Jackson, all originally in print:
State Library of North Carolina biography. This is a solid short biography, divided into sections, laying out the most important events. It could stand for a bit more discussion and interpretation. People and phrases are hyperlinked to external pages of varied quality, and some are broken. His dueling goes unmentioned.
35,000-word mutli-part biography by Hal Morris. As Morris admits, this is largely a distillation of Remini's popular and authoritative Life (mostly, if seems from Remini's one-volume abridgement). It is a good distillation, however, and enjoyable reading. Part of From Revolution to Reconstruction, University of Groningen in Holland.
The Reader's Companion to American History Jackson biography by Sean Wilentz. Good, short bio.
The White House biography. Short bio focuses on his presidential style and actions, and on his temperment. Now, my quibble: It's too bad that the White House biographies are generally the Google-leaders. Although good, they are not generally the best out there. Their inflated status is a side-effect of Google's ranking system (which generally works so well). People link to the White Houseusually for reasons that have nothing to do with the quality of it's history sectionsand these "votes" spill over onto the presidential biographies.
Wikipedia. As you may know, Wikipedia is an "open source" encyclopedia. Anyone can edit it, anyone can reverse an edit. It's amazing how well this works, but there are perils, particularly on controversial or highly-emotional topics (eg., the Trail of Tears). In addition to being a good medium-sized biography, it's a highly-hyperlinked one. These topics include Battle of New Orleans, 1824 Election and a great entry on Nicholas Biddle.
Smithsonian Museum of American History Biography. The bio is nothing special, but you can inspect a great collection of objectshis saber from New Orleans, and two items from the 1828 election, a crock listing his popular majority, and a broadside against him over the militia men he put to death. You can also see a Jackson-themes snuffbox and comb.
National Parks Service Biography with a lot of good images of Jackson.
Facts and mixed resources
Internet Public Library page on Jackson, with hyperlinked lists of cabinet secretaries, some websites and a set of facts.
Short summary of Jackson's presidency from a U.S. History course taught by Anthony A. Ball, Housatonic Community College.