Reveiw article on siRNA: Wang and Carmichael, 2004. (and miRNAs). This article also reviews the PKR/interferon response or what they refer to as the long dsRNA responses. You should read these parts in a coursory manner, just for background and general information. Instead, concentrate on the short dsRNA responses (siRNA and miRNA).

Review article on microRNA: Bartel, 2004.