The OAT is actually more important. I was told this at all 4 of my interviews.
I took my undergrad courses at a very large, competitive, well-recognized university. My GPA was 3.1. However, there is a community college in my city where I could have easily obtained a 3.7 or higher. I am not saying that all universities are better than community colleges. I am just saying that different schools offer different qualities of education.
You can fake a good GPA by going to an easy undergrad institution. BUT YOU CAN'T FAKE A GOOD OAT SCORE (this may happen once in a while if someone lucks out, but this generally doesn't happen).
This is why so many students with competitive GPAs have to retake the OAT if they score below the competitive average. It is rare that someone with great OAT scores is not asked for an interview because their GPA is below the competitive average.
I applied very late in the cycle. Like I said my GPA was 3.1, and I had only completed 90 credits (no bachelor's degree). My application materials were competitive, but my OAT score was exceptional. I was accepted to 2 schools (my top 2 choices), and I believe my OAT score was the biggest reason for that.
IcanSEEanOD:
Here is a link
http://www.opted.org/2006 Profile of Entering Class.pdf
Most schools will want you to have AT LEAST a 300. And as you will see, the competitive average for the OAT is around 330.
I strongly advise that you prepare for the exam well in advance. Try your hardest!! If each piece of your application displays how hard you have worked, you have a great shot!!