I am from Canada. I was going to school in Iowa from 2005-2007 under a F1 visa. In February 2007 I started working in California and in January 2008 I got a TN visa. Wondering if I qualified under the Substantial Presence Test to be a resident alien.

I assume that you were on OPT while working in California.

If so, you were EXEMPT from SPT for 2007 and must file as a non-resident alien for 2007.