As a non-traditional student who will be defending her PhD next week (!), I can tell you that it can be very difficult to overcome the resistance to older students in graduate school. Despite having a lot of practical experience and an extremely strong academic record, I met serious resistance from Profs with whom I interviewed. One of them even told me that Profs like to "make students in their own image" by which she meant to indicate that, since I was approx. her same age, I was too old to be molded. I think that for some, a student with lots of experience outside academia may be threatening.
It can be very difficult to figure out which Profs and programs will take older students. I would start by finding someone who is working in an area that interests you and contacting one or more of his/her students to ask what the relative ages and experience levels of the grad students are. I would also talk to professionals in the field you are interested in - those who have adv. degrees and especially those with connections to a University (either teaching or research). They may be able to provide an introduction to an adviser. I was lucky enough to find an adviser who actually prefers students who have some experience outside of school (I am in an oceanography program), and I am sure there are many like that out there in lots of ecological fields - they can just be difficult to find. Good luck!
