In addition to the Sharn sourcebook, two 22-page adventures, and at least one other sourcebook that I've heard vague mumblings about, there are some novels underway. I believe the novels are by Keith Baker and Matt Forbeck, but I've only heard specifics about Matt's.
Eberron adventures are starting in 113 (which also features a fold-out map) and will continue on a semi-regular basis. (Just in case people who love other campaign settings are worried about this, the campaign setting book has proven that Eberron is close enough to mainstream D&D to keep the adventures useful.)
D&D Online will be set on Eberron's "lost continent" of Xen'drik, and Liquid's D&D real-time strategy game will take place in Xen'drik and Khorvaire.
After that, it all depends on the success of the line. I'm hoping for the best!