My CS2 does not have antialias available or I do not know how to access it so what you can do is open a new document window in the resolution and approximate size you want. IE: 200x200 at a resolution of 300, 800 dpi or what ever is necessary .Type in your text then copy the text to a new layer over your image and drag it where ever you want  I'm no expert but this works for me if I use a font that is rough. TrueType fonts come out pretty smooth at any resolution.