My sister has pcos too, and since her husband doesn't have any issues she was easily able to have children with the help of clomid.

Since it's basically a hormonal disorder, it can effect a variety of things relating to hormone levels. Every women responds differently to how badly they are effected, and having a slim-figure is very helpful as fat around the abdommin also effect hormone feedback loops and can make symptoms worse (my cycles have definitely suffered from my post-baby fat). Whenever any women posts as having irregular cycles (not the 28 day ideal), such as 6 week cycles etc, then I'd advise getting a scan (our health insurance covered this through our regular doctor).

Fertility-wise, the main issue is ovulation. The follicles in the ovaries are basically partly ripened eggs, and can prevent another follicle properly developing to the point of ovulation (meaning that many pcos ladies don't ovulate, or ovulate very seldom). Blood tests, and having regular cycles can rule this out. If you're not ovulating, then clomid is generally prescribed to induce ovulation (obviously you can't do IUI without ovulating, though doctor will monitor that and might be planning on clomid anyway). The other issue can be with egg quality. Even if you do ovulate, those excess hormones from the other follicles can mean the egg doesn't mature perfectly so can lead to lower fertilisation rates. Chances of miscarriage is also higher with pcos ladies, probably in part because of this. Doctors can prescribe metformin as well (an insulin-sensitizing drug), which can help with egg quality and general symptoms.

Hope this helps!