ok i founhd the info i was looking for by looking at the google adsense integration.
for those who want to do somethign similar and have ad colours change with your forum skin you can use
Code:
google_color_border = "$stylevar[alt2_bgcolor_hex]";
google_color_bg = "$stylevar[alt1_bgcolor_hex]";
google_color_link = "$stylevar[body_link_n_fgcolor_hex]";
google_color_text = "$stylevar[body_fgcolor_hex]";
google_color_url = "$stylevar[body_link_n_fgcolor_hex]";
for example. i just transplanted these into my new ad code and they worked fine.
Anyone know if there is a definitive list of all the available stylevar variables written down anywhere?