Reports indicate that third-parties had been, up to now, unable to announce games for Nintendo's 3D successor to the DS.
It has been known for a while that Nintendo plans to show the 3DS in some capacity at E3 next week. It's not known how much they plan to show of their next handheld, which they announced a few months prior, but Game Informer is reporting that third parities will be clear to show their titles for the new system once E3 begins.
What remains to be seen is how far along third-party titles for the 3DS are in their development; we don't know how long developers have had development kits for the new handheld.
The unofficial start of E3 2010 is next Monday, June 14 with the a slate of press conferences that continue into Tuesday, when Nintendo has their press conference and the E3 show floor opens. Besides the 3D screens, very little is known about the 3DS, but expect all that to change in a week.