Congrats!
I remember the day I got that email too! It was a big step for me; I remembers saying to my spouse (after 20 pages), "well, I don't think I'll be able to get more than 22 or 23 pages".. (Note: I now have 200 pages!!!

)
One thing that helped me to get new page ideas was to register for Yahoo Answers and answer questions related to my niche. I would source a page from my site in the source box that was relevant to my answer. Every once in a while someone would ask a question that I hadn't addressed.. and voila... new page!
Good Luck, Liz!