When you add MobileMe to your iPhone through your settings, when you are typing in your
Email@me.com and your password, USE ALL LOWER CASE LETTERS!!!
For about 3 hours I couldnt get my MobileMe to sync to my iPhone, it would go from, macbook pro -> to cloud, and just sit there it wouldn't sync to iPhone because I kept using capital letters in my
email@me.com! I finally tried with all lower case letters and it worked INSTANTLY!
Hope this helps.