IGN confirms that 3DS launch details will be announced on a press conference at the Makuhari Messe on September 29th. At the end of an article about the sales of Pokémon games, Anoop Gantayat wrote the following:

Nintendo will be announcing its 3DS launch strategy on the 29th during a press conference at the Makuhari Messe (the same venue as the Tokyo Game Show, which Nintendo does not attend) in Chiba, Japan.

So it seems that, after skipping 2009, Nintendo is getting back to their (relatively young) tradition of fall conferences, where a lot of new games and hardware were revealed in the past years in early October. Here’s a rundown of interesting things were revelead in the past years:

2006: Wii price, release date, launch games list and additional details
2007: DS Demo Channel, WiiWare launch date, Wii Fit
2008: DSi, Wii storage, Wii Speak
2009: Skipped
2010: 3DS

Judging from past year’s showings, we can expect a hot wednesday. Stay tuned for all the good stuff, it’s less than 6 days to go!