M.W.
While I have no first hand experience with infertility, I was a gestational surrogate and have been "involved" with infertility issues for a few years. Why don't you check out www.fertilityneighborhood.com for some advice from the ladies who have dealt with the nightmare of infertility first hand. You'll get some help with how to tell your friend and some good advice on how to be the kind of friend she needs through her trying time.
Best of luck with your pregnancy! Here's to a healthy nine months.