A related discussion, It has been suggested that my daughter has ADHD. was started.
Some of the things you describe could be features of a child on the autism spectrum, but they might also be representative of a child with a possible communication problem. I encourage you to take your son to your pediatrician and discuss your concerns with him or her. If your child’s doctor believes further assessment in necessary, then I recommend that you find an assessment team familiar with young children and autism spectrum disorders (ASD). A speech and language pathologist should be a member of the team given your description of the communication problems. (I am not a speech and language pathologist, but 3 or 4 word phrases for a 2-1/2-year-old doesn’t sound all that atypical to me. The eye contact and lack of responsiveness to name should be of concern.)
In the meantime you may wish to take a look at the websites below. They have information about early identification of children with ASD
About.com Pediatrics
http://pediatrics.about.com/od/weeklyquestion/a/04_signs_autism.htm
American Academy of Pediatrics
http://www.aap.org/healthtopics/Autism.cfm
First Signs
http://www.firstsigns.org/