Do you mean Guitar Hero for the D.S. or for a major platform? Warriors of Rock is expected to be released this fall for the major platform consoles (PS3, 360, Wii), but I haven't heard of any plans for a new handheld game.
Yes, Warriors of Rock is coming out Sept. 28 on consoles. As for DS, probably not. With the DSi out and soon the 3DS, the exclusion of the GBA slot is handicapping the GH DS franchise. Of course, maybe they will find a way to do it without the GBA slot, but nobody knows yet.
There is, however, going to be Rock Band 3 for the DS, but it will play similar to Lego Rock Band DS, so that's disappointing...
well no guitar hero games on ds but for dj hero there is going to be djhero3d for 3dds i think its going to be released near the time of arrival of the 3dds