Yeah, Nintendo will have 2 E3 presentations this year! I can't wait!
The first presentation is about the hardware, such as stuff about the 3DS and the Wii U.
The second presentation will showcase new software.
You can catch the first presentation on June 5th at 9am PDT, and the second presentation on June 6th at 6pm PDT. Maybe you can find a time converter for your area on Google or something. ^^
Oh, and you can catch both presentations live on
this site right here. : D
EDIT: The main press conference tomorrow (June 5th) will mainly focus on the Wii U. Sure, there MAY be a few pieces of info about the 3DS, but there will be a LOT more 3DS stuff on the June 6th presentation.
There is also a rumor going around that Nintendo may announce a 3DS XL... I personally don't think it's true, but you never know for sure until it's confirmed. Just throwing it out there, just in case.