Here’s another Practical Online Marketing Two Thumbs Up Award Winner
This article by Brad Miller does an A+ job of explaining the use of 301 redirects vs. using the canonical attribute when it comes to search engine indexing.
This information and understanding it also figures into your overall SEO strategy.
In addition to an easy-to-understand explanation, it also discusses the pros and cons of using each.
301 Redirects vs. Canonical (source: Search Engine Watch)