I have dual citizenship of USA and Portugal and want to apply for a tourist visa to China

I have a dual citizenship of USA and Portugal and currently living in Portugal. I want to apply for a tourist visa to travel from Portugal to China in September/October of 2012 using my USA passport. I want to use my USA passport because my tickets were bought using the USA passport.
In the past I have lived and worked in China for more than 10 years and have had multiple Chinese visas for both work and tourist. I am currentlky retired and wish to visit china as a tourist to meet some of my former colleagues and friends.
Please advise which visa application form I must use and if possible send it to me as attachments to me email address below.