I just copied and pasted one of my previous posts, I actually think it was your thread (forgive me if I am wrong), answering a similiar question...
Fill out and submit your application, leaving the ACT part blank, and contact the school to let them know you will be taking the ACT later on (some applications have a small box you can check). Next, contact ACT and tell them to send your scores directly to that college or university; you can do this from http://www.actstudent.org/ if you are registered with them. Your application will meet the deadline but will not be processed until your scores are in.