I’m want to multitexture an object:
the main texture coords are explicity given but the second texture is to be sphere mapped
and it has an alpa channel, I actually blend it with glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)

any ideas?

What is the problem? Setting up sphere mapping texture coordinate generation on the second texture unit, or serring up proper texture combine function for the blending? If it’s about the blending, also say what effect you want, since there are a zillion different effects that can be achieved with blending and texture combine functions.