What to know before debating type systems is a really good article discussing static and dynamic type systems and type inference. I found it via Dry Sellers CodeBetter.com blog post Sunday Thought: Embracing the Type System.
Related to that, if you’d like to learn more about type inference algorithms, have a read of Code Commit’s blog post What is Hindley-Milner? (and why is it cool?). The post gives an easy to understand overview of the Hindley-Milner type inference algorithm.