Metformin

So I was officially diagnosed with PCOS yesterday. Apparently I've had polycystic ovaries for a long time but my docs never told me. I have had one miscarriage and one full term pregnancy. Now we are TTC number two and my cycles are worse than they've been since before I went on BCP years ago. My doctor prescribed Metformin. Is there anything I should know about it? He said I need to start taking it once a day for a week and then go twice a day after one week...anyone else have experience with this drug? Did it help you get pregnant?