Both Toon Zone and ICv2 have written of a supposed Entertainment Tonight report that there will be a sequel to the recently-released Transformers movie (which has already been a line of toys, several animated TV series, a comic book and a feature-length animated film).

However, my scan of the ET site has not brought up anything of the sort, and while a couple articles from other sites do allude to the possibility of a sequel, I see nothing that could be construed as an official announcement.