According to the official website, the second movie of "Tengen Toppa Gurren Lagann
" titled "Tengen Toppa Gurren Lagann Movie Lagann-hen
" will be shown in the theaters in the Golden Week of 2009. Golden Week is a Japanese holiday week and usually spans from April 29th to May 5th.
The movie of "Eureka Seven
" called "Eureka Seven: Pocket ga Niji de Ippai
" will also be premiered in the same week.
Source: Gurren Lagan Official Website
Source: Eureka Seven Movie official Website
The re-filming of the first movie for the DVD release has already been started and about 100 scenes will be re-drawn. But it will take long before the DVD is available in the stores.
Source: Gainax official blog
Edited on Dec 30th===============
The premiere date of Gurren Lagan Movie was announced to be April 25th, 2009.
Source: Official Website