I'm looking for a Sigma lens for my Nikon D60, for a beginner like me, it's so hard to tell which one can fit (the website may list the name as 'SIGMA 28-135mm F3.8-5.6 IF SAF',or something like that) . what should i look for then?
You need to make sure that the lens has a Nikon mount (the ring on the lens where it fits into the camera). The same Sigma lens can be manufactured with different mounts to fit different cameras.