Tga And Blending

Hi , I’d Like to use a TGA Image as a Texture to take advantage of the alpha Channel , I have no problems With loading TGA files , all I wanna know is , Which BlendFunc should I use , and do I need to do anything else otherthan Sorting…
like do I have 2 use glColor4f before Rendering the Quad With the TGA Texture , and if I need 2 do that , What Alpha value should I use …

this is what i do:

glAlphaFunc(GL_GREATER, 0.83f);