There is such a range of race and color in Colombia...just like in the US. From very fair skinned to very dark (Afro-Colombian) and while most Colombians have dark hair and eyes, don't be surprised to see natural blondes and even more of the bottled variety.
Its hard to be delicate when talking about issues of race and class...but I will tell you my general impressions. In general the native population and afro-colombians are considered lower class. They also tend to have the darkest skin tones. The lightest skinned Colombians tend to have a more direct lineage to Spain or other European heritage. I wish I could say race isn't an issue in Colombia...or in the US for that matter, but I do think that racism still exists. And I also think that the class differences in Colombia are more extreme than in the US.
I tried to put that as delicately as I could. I sincerely hope that I do not offend anyone here.